Filed Pursuant to Rule 424(b)(5)
Registration No. 333-270760

PROSPECTUS SUPPLEMENT

(To prospectus dated April 14, 2023)

634,500 Shares of Common Stock

Warrants to Purchase 634,500 Shares of Common Stock

We are offering 634,500 shares of our common stock, par value $0.001 per share, and accompanying warrants to purchase up to 634,500 shares of our common stock, in a registered direct offering to a limited number of investors pursuant to this prospectus supplement and the accompanying prospectus. Our common stock is listed on the Nasdaq Global Select Market under the symbol “ASMB.” On June 14, 2024, the last reported sale price of shares of our common stock on the Nasdaq Global Select Market was $15.39 per share.

The combined public offering price for each share of common stock and accompanying warrant to purchase 634,500 shares of common stock is $15.46. The warrants have an exercise price of $17.00 per share, are exercisable immediately and will expire five years from the date of issuance. We are also offering the shares of our common stock that are issuable from time to time upon exercise of the warrants.

The shares of common stock and the accompanying warrants can only be purchased together in this offering but will be issued separately and not as a unit. There is no established public trading market for the warrants, and we do not expect a market to develop. We do not intend to apply for listing of the warrants on The Nasdaq Global Select Market or any securities exchange or nationally recognized trading system. Without an active trading market, the liquidity of the warrants will be limited.

We are a “smaller reporting company” as defined under the federal securities laws and, as such, we have elected to comply with reduced reporting requirements for this prospectus supplement and may elect to do so in future filings.

INVESTING IN OUR COMMON STOCK INVOLVES RISKS THAT ARE DESCRIBED IN THE “RISK FACTORS” SECTION BEGINNING ON PAGE S-4 OF THIS PROSPECTUS SUPPLEMENT, ITEM 1A. (“RISK FACTORS”) BEGINNING ON PAGE 20 OF OUR ANNUAL REPORT ON FORM 10-K FOR THE FISCAL YEAR ENDED DECEMBER 31, 2023, FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MARCH 28, 2024, AND ITEM 1A. (“RISK FACTORS”) BEGINNING ON PAGE 23 OF OUR QUARTERLY REPORT ON FORM 10-Q FOR THE QUARTERLY PERIOD ENDED MARCH 31, 2024, FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 8, 2024, WHICH ARE INCORPORATED BY REFERENCE HEREIN, AS WELL AS THE OTHER INFORMATION INCLUDED AND INCORPORATED BY REFERENCE HEREIN.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Delivery of the shares of common stock and warrants is expected to be made on or about June 17, 2024 only in book-entry through the facilities of The Depository Trust Company.

Prospectus Supplement dated June 17, 2024

TABLE OF CONTENTS

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document contains two parts. The first part is this prospectus supplement, which describes the specific terms of this offering and also supplements and updates information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part is the accompanying prospectus, which provides more general information, some of which may not apply to this offering. If the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus or in any document incorporated by reference herein or therein that was filed with the Securities and Exchange Commission (“SEC”) before the date of this prospectus supplement, you should rely on the information set forth in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a subsequently filed document deemed incorporated by reference in the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

You should rely only on the information contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus. We have not authorized anyone to provide you with information that is in addition to or different from that contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus or contained in any permitted free writing prospectuses we have authorized for use in connection with this offering. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may provide.

We are offering to sell, and seeking offers to buy, shares of our common stock and accompanying warrants only in jurisdictions where such offers and sales are permitted. The information contained in this prospectus supplement, the accompanying prospectus and any related free writing prospectus, as well as the documents incorporated by reference herein and therein is accurate only as of their respective dates (or any such earlier date as of which such information is given), regardless of the time of delivery of any such document or the time of any sale of the common stock or the accompanying warrants. Our business, financial condition, results of operations and prospects may have changed materially since those dates. It is important for you to read and consider all information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus and any free writing prospectus in making your investment decision. You should read both this prospectus supplement, the accompanying prospectus, any related free writing prospectus, as well as the documents incorporated by reference into this prospectus supplement and the accompanying prospectus and the additional information described under the section titled “Where You Can Find More Information” in this prospectus supplement and in the accompanying prospectus, before investing in our securities.

When used in this prospectus supplement, the terms “Assembly Bio,” “Assembly,” the “Company,” “we,” “our” and “us” refer to Assembly Biosciences, Inc. and its consolidated subsidiaries, unless otherwise specified or the context otherwise requires.

This prospectus supplement, the accompanying prospectus and the documents incorporated by reference contain estimates, projections and other information concerning our industry, our business, and the markets for certain diseases, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Information that is based on estimates, forecasts, projections, market research or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained this industry, business, market and other data from reports, research surveys, studies and similar data prepared by market research firms and other third parties, industry, medical and general publications, government data and similar sources. Additionally, while such information has been obtained from sources believed to be reliable, there can be no assurance as to the accuracy or completeness of the included information. We have not independently verified any of the data from third-party sources, nor have we ascertained the

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underlying economic assumptions relied upon therein. While such information is believed to be reliable for the purposes used herein, none of the Company, its affiliates, nor their respective directors, officers, employees, members, partners, stockholders or agents make any representation or warranty with respect to the accuracy of such information.

No action is being taken in any jurisdiction outside the United States to permit a public offering of the securities or possession or distribution of this prospectus supplement or the accompanying prospectus in that jurisdiction. Persons who come into possession of this prospectus supplement or the accompanying prospectus in jurisdictions outside the United States are required to inform themselves about and to observe any restrictions as to this offering and the distribution of this prospectus supplement or the accompanying prospectus applicable to that jurisdiction.

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RISK FACTORS

Investing in our securities involves a high degree of risk. Before making an investment decision, you should carefully consider the risks described below and in our Annual Report on Form 10-K for the year ended December 31, 2023 and our Quarterly Report on Form 10-Q for the quarter ended March 31, 2024 incorporated by reference into this prospectus supplement and the accompanying prospectus, any amendment or update thereto reflected in our subsequent filings with the SEC, and all of the other information into this prospectus supplement and the accompanying prospectus, including our financial statements and related notes incorporated by reference in this prospectus supplement and the accompanying prospectus. If any of these risks is realized, our business, financial condition, results of operations and prospects could be materially and adversely affected. In that event, the trading price of our common stock could decline or the value of the warrants offered and sold in this offering could decline, and you could lose part or all of your investment. Additional risks and uncertainties that are not yet identified or that we currently believe to be immaterial may also materially harm our business, operating results and financial condition and could result in a complete loss of your investment.

Risks Related to this Offering

We have broad discretion in the use of the net proceeds from this offering and our existing cash and may not use them effectively.

Our management will have broad discretion in the application of the net proceeds from this offering, including for any of the purposes described in the section titled “Use of Proceeds,” as well as our existing cash, and you will be relying on the judgment of our management regarding such application. You will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. Our management might not apply the net proceeds or our existing cash in ways that ultimately increase the value of your investment. If we do not invest or apply the net proceeds from this offering or our existing cash in ways that enhance stockholder value, we may fail to achieve expected results, which could cause our stock price to decline. Pending their use, we may invest the net proceeds from this offering in short-term investments that do not produce significant income or that may lose value. Such investments may not yield a favorable return to our stockholders.

If you purchase our common stock in this offering, you will incur immediate and substantial dilution in the book value of your shares.

Investors purchasing shares of common stock in this offering will pay a price per share that substantially exceeds the as adjusted book value per share of our tangible assets as of March 31, 2024 after subtracting our liabilities. Our net tangible book value as of March 31, 2024 was approximately $32.6 million, or $5.95 per share of our common stock, based upon 5,482,752 shares of common stock outstanding on March 31, 2024. Based on the combined public offering price of $15.46 per share, and after deducting estimated offering expenses payable by us, our as adjusted net tangible book value as of March 31, 2024, would have been approximately $42.1 million, or approximately $6.88 per share of our common stock. As a result, investors purchasing shares of common stock in this offering will incur immediate dilution of $8.58 per share.

This dilution is due to the substantially lower price paid by some of our investors who purchased shares prior to this offering as compared to the price offered to the public in this offering and the exercise of stock options granted to our employees, directors and consultants. In addition, we have a significant number of stock options, warrants and RSUs outstanding. The exercise of any of these outstanding options and warrants and the vesting and settlement of any of these RSUs would result in additional dilution. As a result of the dilution to investors purchasing shares in this offering, investors may receive significantly less than the purchase price paid in this offering, if anything, in the event of our liquidation. Further, because we expect we will need to raise additional capital to fund our future activities, we may in the future sell substantial amounts of common stock or securities convertible into or exchangeable for common stock. For a further description of the dilution that you will experience immediately after this offering, see the section titled “Dilution.”

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There is no public market for the warrants being offered in this offering.

There is no established public trading market for the warrants being offered in this offering, and we do not expect a market to develop. In addition, we do not intend to apply to list these warrants on any securities exchange or nationally recognized trading system, including The Nasdaq Global Select Market. Without an active market, the liquidity of these warrants will be limited.

Holders of warrants purchased in this offering will have no rights as common stockholders until such holders exercise their warrants and acquire our common stock.

Until holders of the warrants acquire shares of our common stock upon exercise of such warrants, the holders will have no rights with respect to the shares of our common stock underlying such warrants, such as voting rights or the rights to receive dividends. Upon exercise of the warrants, the holders will be entitled to exercise the rights of a common stockholder only as to matters for which the record date occurs after the exercise.

The warrants being offered may not have value.

The warrants being offered by us in this offering have an exercise price of $17.00 per share of common stock, subject to certain adjustments, and expire five years from the date of issuance, after which date any unexercised warrants will expire and have no further value. In the event that the market price of our common stock does not exceed the exercise price of the warrants during the period when they are exercisable, the warrants may not have any value.

We may not receive any additional funds upon the exercise of the warrants being offered.

In certain limited circumstances, each warrant may be exercised by way of a cashless exercise, meaning that the holder may not pay a cash purchase price upon exercise, but instead would receive upon such exercise the net number of shares of our common stock determined according to the formula set forth in the warrant. Accordingly, we may not receive any additional funds upon the cashless exercise of the warrants or if the warrants altogether are not exercised at all.

Significant holders or beneficial holders of our common stock may not be permitted to exercise warrants that they hold.

Holders of the warrants will not be entitled to exercise any portion of any warrant which, upon giving effect to such exercise, would cause the aggregate number of shares of our common stock beneficially owned by the holder (together with its affiliates) to exceed a specified percentage of the number of shares of our common stock outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the warrants. As a result, you may not be able to exercise your warrants for shares of our common stock at a time when it would be financially beneficial for you to do so. In such circumstance you could seek to sell your warrants to realize value, but you may be unable to do so in the absence of an established trading market for the warrants.

Sales of a substantial number of shares of our common stock, including any shares issuable upon exercise of any warrants, in the public market could cause our stock price to fall.

Sales of a substantial number of shares of our common stock, including any shares issuable upon exercise of any warrants issued in this offering, in the public market or the perception that these sales might occur could depress the market price of our common stock and could impair our ability to raise capital through the sale of additional equity securities. We are unable to predict the effect that sales may have on the prevailing market price of our common stock. In addition, the sale of substantial amounts of our common stock could adversely impact its price. As of March 31, 2024, we had outstanding 5,482,752 shares of our common stock, options to purchase

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1,026,696 shares of our common stock (of which 520,884 were exercisable as of that date) and 103,752 shares of our common stock underlying RSUs. The sale or the availability for sale of a large number of shares of our common stock in the public market could cause the price of our common stock to decline.

We have agreed that for a period of 60 days after the closing date of this offering, subject to specified exceptions, neither we nor any of our subsidiaries will (i) issue, enter into any agreement to issue or announce the issuance or proposed issuance of any shares of our common stock or securities convertible into or exercisable or exchangeable for any shares of our common stock, or (ii) effect or enter into an agreement to effect any issuance of our common stock or securities convertible into or exercisable or exchangeable for any shares of our common stock involving a variable rate transaction.

Because we have no current plans to pay cash dividends on our common stock for the foreseeable future, you may not receive any return on investment unless you sell your common stock for a price greater than that which you paid for it.

We intend to retain future earnings, if any, for future operations and expansion of our business and have no current plans to pay any cash dividends for the foreseeable future. The declaration, amount and payment of any future dividends on shares of common stock will be at the sole discretion of our Board of Directors. Our Board of Directors may take into account general and economic conditions, our financial condition and results of operations, our available cash and current and anticipated cash needs, capital requirements, contractual, legal, tax and regulatory restrictions, implications on the payment of dividends by us to our stockholders or by our subsidiaries to us and such other factors as our Board of Directors may deem relevant. In addition, our ability to pay dividends may be limited by covenants in connection with any indebtedness we or our subsidiaries incur. As a result, you may not receive any return on an investment in our common stock unless you sell our common stock for a price greater than that which you paid for it.

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CAUTIONARY STATEMENT ON FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus, any related free writing prospectus and the documents that we incorporate by reference herein and therein, contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Exchange Act. All statements other than statements of historical facts contained in this prospectus supplement, the accompanying prospectus, any related free writing prospectus and any documents incorporated by reference, including statements regarding this offering, the concurrent Private Placement, the intended use of proceeds from this offering, the timing of commencement of future clinical studies involving our therapeutic product candidates, our ability to successfully complete, and receive favorable results in, clinical studies for our product candidates, our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward-looking statements. These statements are often, but are not always, made through the use of words or phrases such as “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will,” “would”, “might”, “hopes”, “forecast”, “design”, “goal” and similar expressions, or the negative of these terms, or similar expressions. Accordingly, these statements involve estimates, assumptions, risks and uncertainties which could cause actual results to differ materially from those expressed in them. Any forward-looking statements are qualified in their entirety by reference to the factors discussed throughout this prospectus supplement, the accompanying prospectus, any related free writing prospectus, as well as the information and the documents incorporated by reference herein and therein, and in particular those factors referenced in the sections titled “Risk Factors.”

This prospectus supplement, the accompanying prospectus and the information and documents incorporated by reference herein and therein contain forward-looking statements that are based on our management’s belief and assumptions and on information currently available to our management. These statements relate to future events or our future financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. Forward-looking statements include, but are not limited to, statements about:

These forward-looking statements are neither promises nor guarantees of future performance due to a variety of risks and uncertainties, many of which are beyond our control, which could cause actual results to differ materially from those indicated by these forward-looking statements, including, without limitation the risk factors and cautionary statements described in other documents that we file from time to time with the SEC, specifically under “Item 1A: Risk Factors” and elsewhere in our Annual Report on Form 10-K for the year ended December 31, 2023 and our Quarterly Report on Form 10-Q for the quarter ended March 31, 2024 and the section of this prospectus supplement and the accompanying prospectus titled “Risk Factors.”

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The forward-looking statements in this prospectus supplement, the accompanying prospectus, any related free writing prospectus and the documents incorporated by reference represent our views as of their respective dates. We anticipate that subsequent events and developments will cause our views to change. However, while we may elect to update these forward-looking statements at some point in the future, we assume no obligation to update or revise any forward-looking statements except to the extent required by applicable law. You should, therefore, not rely on these forward-looking statements as representing our views as of any date subsequent to the dates on which they were made.

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USE OF PROCEEDS

We estimate that the net proceeds to us from this offering, after deducting the estimated offering expenses payable by us, will be approximately $9.6 million. We plan to use the net proceeds of this offering for general corporate purposes.

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DILUTION

If you invest in our securities in this offering, your ownership interest will be diluted to the extent of the difference between the combined public offering price per share of our common stock and warrants in this offering and the as adjusted net tangible book value per share of our common stock immediately after this offering.

As of March 31, 2024, we had net tangible book value of approximately $32.6 million, or $5.95 per share of our common stock, based upon 5,482,752 shares of our common stock outstanding as of that date. Historical net tangible book value per share is equal to our total tangible assets, less total liabilities, divided by the number of outstanding shares of our common stock. Dilution in net tangible book value per share represents the difference between the amount per share paid by purchasers of shares of common stock in this offering and the net tangible book value per share of our common stock immediately after this offering.

After giving effect to the sale of 634,500 shares of common stock and warrants in this offering at the combined public offering price of $15.46 per share, and after deducting estimated offering expenses payable by us, our as adjusted net tangible book value as of March 31, 2024 would have been approximately $42.1 million, or approximately $6.88 per share of common stock. This represents an immediate increase in as adjusted net tangible book value of $0.93 per share to our existing stockholders and an immediate dilution of $8.58 per share to investors participating in this offering at the combined public offering price.

Dilution per share to new investors is determined by subtracting net tangible book value per share after this offering from the combined public offering price per share paid by new investors. The following table illustrates this per share dilution to new investors:

The table and discussion above are based on 5,482,752 shares of common stock outstanding as of March 31, 2024, and exclude:

Except as otherwise indicated, all information in this prospectus supplement assumes:

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To the extent that any options or warrants are exercised, any RSUs vest and are settled, new equity awards are issued under our equity incentive plans, or we otherwise issue additional shares of common stock in the future (including shares issued in connection with strategic and other transactions), there will be further dilution to new investors.

We expect to continue to raise capital when and as needed and at the time and in the manner most advantageous to us. To the extent that additional capital is raised through the sale of equity, equity-linked, convertible debt securities or other securities that are exercisable for, or convertible into, shares of our common stock, the issuance of these securities could result in further dilution to our stockholders.

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DIVIDEND POLICY

We have never declared or paid any dividends and do not anticipate paying any dividends on our common stock in the foreseeable future. We currently intend to retain all available funds and any future earnings to fund the development and growth of our business. Any future determination to declare dividends will be subject to the discretion of our board of directors and will depend on various factors, including applicable laws, our results of operations, financial condition, future prospects and any other factors deemed relevant by our board of directors. Investors should not purchase our securities with the expectation of receiving cash dividends.

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DESCRIPTION OF SECURITIES WE ARE OFFERING

Common Stock

We are offering shares of our common stock in this offering. See “Description of Securities” in the accompanying prospectus, as updated by Exhibit 4.2 to our Annual Report on From 10-K for the fiscal year ended December 31, 2023 incorporated by reference herein, for more information regarding our shares of common stock.

Warrants

The following summary of certain terms and provisions of the warrants that are being offered hereby is not complete and is subject to, and qualified in its entirety by, the provisions of the warrant, the form of which will be filed as an exhibit to a Current Report on Form 8-K in connection with this offering and incorporated by reference into the registration statement of which this prospectus supplement forms a part. Prospective investors should carefully review the terms and provisions of the form of warrant for a complete description of the terms and conditions of the warrants.

Duration and Exercise Price

Each warrant offered hereby has an initial exercise price per share equal to $17.00. The warrants are immediately exercisable and will expire on the fifth anniversary of the original issuance date. The exercise price and number of shares of common stock issuable upon exercise is subject to adjustment, as set forth in the warrant, in the event of stock dividends, stock splits, stock combinations or issuances by reclassification affecting our common stock and the exercise price.

Exercisability

The warrants will be exercisable, at the option of each holder, in whole or in part, by delivering to us a duly executed exercise notice accompanied by payment in full for the number of shares of our common stock purchased upon such exercise (except in the case of a cashless exercise as discussed below). No fractional shares of common stock will be issued in connection with the exercise of a warrant. In lieu of fractional shares, we will either pay the holder an amount in cash equal to the fractional amount multiplied by the exercise price or round up to the next whole share.

A holder of the warrant will not be entitled to exercise any portion of such warrant that, upon giving effect to such exercise, would cause the aggregate number of shares of our common stock beneficially owned by such holder (together with its affiliates and any other persons whose beneficial ownership of common stock would be aggregated with the holder for purposes of Section 13(d) of the Exchange Act) to exceed 9.99% (or 4.99% at the election of the holder, or 19.99% in the case of a holder who beneficially owns more than 9.99% of our common stock immediately prior to the issue date) of the total number of then issued and outstanding shares of common stock, as such percentage ownership is determined in accordance with the terms of the warrant.

Cashless Exercise

If, at the time a holder exercises its warrants, a registration statement registering the issuance of the shares of common stock underlying the warrants under the Securities Act is not then effective or available, then in lieu of making the cash payment otherwise contemplated to be made to us upon such exercise in payment of the aggregate exercise price, the holder may elect instead to receive upon such exercise (either in whole or in part) the net number of shares of common stock determined according to a formula set forth in the warrants.

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Fundamental Transaction

In the event of any fundamental transaction, as described in the warrants and generally including any merger with or into another entity, sale of all or substantially all of our assets, tender offer or exchange offer, or reclassification of our shares of common stock, then upon any subsequent exercise of a warrant, the holder will have the right to receive as alternative consideration, for each share of common stock that would have been issuable upon such exercise immediately prior to the occurrence of such fundamental transaction, the number of shares of common stock of the successor or acquiring corporation of our company, if it is the surviving corporation, and any additional consideration receivable upon or as a result of such transaction by a holder of the number of shares of common stock for which the warrant is exercisable immediately prior to such event.

Transferability

Subject to applicable laws, a warrant may be transferred at the option of the holder upon surrender of the warrant to us together with the appropriate instruments of transfer and payment of funds sufficient to pay any transfer taxes (if applicable).

Exchange Listing

There is no trading market available for the warrants on any securities exchange or nationally recognized trading system. We do not intend to list the warrants on The Nasdaq Global Market or any securities exchange or nationally recognized trading system.

Right as a Shareholder

The holders of the warrants (as a result of their warrants) do not have the rights or privileges of holders of our common stock, including any voting rights, until they exercise their warrants.

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MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS

The following discussion is a summary of the U.S. federal income tax considerations generally applicable to the ownership and disposition of our common stock and warrants (collectively, our “securities”). This summary is based upon U.S. federal income tax law as of the date of this prospectus supplement, which is subject to change or differing interpretations, possibly with retroactive effect. This summary does not discuss all aspects of U.S. federal income taxation that may be important to particular investors in light of their individual circumstances, including investors subject to special tax rules (e.g., financial institutions, insurance companies, broker-dealers, tax-exempt organizations (including private foundations), investors that have elected the mark-to-market method of tax accounting, S corporations, regulated investment companies, real estate investment trusts, partnerships (including other entities or arrangements treated as partnerships for U.S. federal income tax purposes) or investors holding our securities through such entities, passive foreign investment companies, controlled foreign corporations, investors that will hold our common stock or warrants as part of a straddle, hedge, conversion, constructive sale or other integrated transaction for U.S. federal income tax purposes, expatriates, or investors that have a functional currency other than the U.S. dollar), all of whom may be subject to tax rules that differ materially from those summarized below. In addition, this summary does not discuss other U.S. federal tax consequences (e.g., estate or gift tax), any state, local, or non-U.S. tax considerations or the Medicare tax or any minimum tax. In addition, this summary is limited to investors that will hold our securities as “capital assets” (generally, property held for investment) under the Internal Revenue Code of 1986, as amended (the “Code”). No assurance can be given that the Internal Revenue Service (“IRS”) would not assert, or that a court would not sustain a position contrary to any of the tax aspects set forth below.

For purposes of this summary, a “U.S. Holder” is a beneficial holder of our securities that, for U.S. federal income tax purposes is:

A “non-U.S. Holder” is a beneficial holder of our securities that is neither a U.S. Holder nor a partnership for U.S. federal income tax purposes.

THIS DISCUSSION OF U.S. FEDERAL INCOME TAX CONSIDERATIONS IS FOR GENERAL INFORMATION PURPOSES ONLY AND IS NOT TAX ADVICE. PROSPECTIVE HOLDERS SHOULD CONSULT THEIR TAX ADVISORS CONCERNING THE U.S. FEDERAL INCOME TAX CONSEQUENCES TO THEM OF OWNING AND DISPOSING OF OUR SECURITIES, AS WELL AS THE APPLICATION OF ANY, STATE, LOCAL AND NON-U.S. INCOME AND OTHER TAX CONSIDERATIONS.

U.S. Holders

Allocation of Purchase Price Among Shares and Warrants

Because our common stock is sold together with the accompanying warrants, a purchaser of shares of our common stock and the accompanying warrants must allocate its purchase price between each share of our common stock and the accompanying warrant based on their respective relative fair market values at the time of

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issuance. This allocation of the purchase price will establish the U.S. Holder’s initial tax basis for U.S. federal income tax purposes for each share of our common stock and warrant. A U.S. Holder’s allocation of the purchase price is not binding on the IRS or the courts, and no assurance can be given that the IRS or the courts will agree with a U.S. Holder’s allocation. Each U.S. Holder should consult its tax advisor regarding the allocation of the purchase price among the shares of common stock and warrants.

Distributions on Our Common Stock

We have not paid and do not anticipate paying dividends. However, any dividends we pay to U.S. Holders will generally constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. Distributions in excess of current and accumulated earnings and profits generally will constitute a return of capital that will be applied against and reduce (but not below zero) the U.S. Holder’s adjusted tax basis in its shares of common stock. Any remaining excess generally will be treated as gain realized on the sale or other taxable disposition of such shares of common stock and will be treated as described below under “U.S. Holders—Sale, Exchange or Other Taxable Disposition of Common Stock and Warrants.”

Dividends we pay to a corporate U.S. Holder will generally qualify for the dividends received deduction if the requisite holding period is satisfied. With certain exceptions, and provided certain holding period requirements are met, dividends we pay to a non-corporate U.S. Holder will generally constitute “qualified dividends” that will be subject to tax at a lower capital gain tax rate.

Sale, Exchange or Other Taxable Disposition of Common Stock and Warrants

Upon a sale, exchange or other taxable disposition of shares of common stock or warrants, a U.S. Holder will recognize capital gain or loss in an amount equal to the difference between (1) the amount realized upon such disposition and (2) the U.S. Holder’s tax basis in the such share of our common stock or warrants. Such gain or loss will generally be treated as long-term capital gain or loss if the shares of common stock or warrants are held by the U.S. Holder for more than one year at the time of such disposition. If a warrant is allowed to lapse unexercised, a U.S. Holder generally will recognize a capital loss equal to such holder’s tax basis in the warrant. The deductibility of capital losses is subject to certain limitations.

Exercise of a Warrant

Except as discussed below with respect to the cashless exercise of a warrant, a U.S. Holder will not recognize gain or loss upon the exercise of a warrant. The U.S. Holder’s tax basis in the share of our common stock received upon exercise of the warrant will generally be an amount equal to the sum of (i) the U.S. Holder’s adjusted tax basis in the warrant and (ii) the exercise price of such warrant. A U.S. Holder’s adjusted tax basis in a warrant generally is equal to the U.S. Holder’s initial investment in the warrant, increased by any constructive distributions that are treated as dividends and decreased by any constructive distributions treated as returns of capital. It is unclear whether a U.S. Holder’s holding period for the common stock received upon exercise of the warrant would commence on the date of exercise of the warrant or the day following the date of exercise of the warrant; however, in either case the holding period will not include the period during which the U.S. Holder held the warrants.

The tax consequences of a cashless exercise of a warrant are not entirely clear under current tax law. A cashless exercise may not be subject to tax, either because the exercise is not a realization event or because the exercise is treated as a recapitalization for U.S. federal income tax purposes. In either situation, a U.S. Holder’s tax basis in the common stock received would generally equal the holder’s tax basis in the warrant. If the cashless exercise were treated as not being a realization event, it is unclear whether a U.S. Holder’s holding period for the common stock would commence on the date of exercise of the warrant or the day following the date of exercise of the warrant. If, however, the cashless exercise were treated as a recapitalization, the holding period of the common stock would include the holding period of the warrant.

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It is also possible that a cashless exercise of a warrant could be treated as a taxable exchange in which gain or loss is recognized. In such event, a U.S. Holder would be deemed to have surrendered a number of warrants having a value equal to the exercise price. The U.S. Holder would recognize capital gain or loss in an amount equal to the difference between the exercise price of the warrants deemed exercised and the U.S. Holder’s tax basis in the warrants deemed surrendered. In this case, a U.S. Holder’s tax basis in the common stock received would equal the sum of the U.S. Holder’s initial investment in the warrants deemed exercised and the exercise price of such warrants. It is unclear whether a U.S. Holder’s holding period for the common stock would commence on the date of exercise of the warrant or the day following the date of exercise of the warrant.

Due to the absence of authority on the U.S. federal income tax treatment of a cashless exercise, including when a U.S. Holder’s holding period would commence with respect to the common stock received, there can be no assurance which, if any, of the alternative tax consequences and holding periods described above would be adopted by the IRS or a court. Accordingly, U.S. Holders are urged to consult their tax advisors regarding the tax consequences of a cashless exercise.

Possible Constructive Distributions

The terms of each warrant provide for an adjustment to the number of shares of common stock for which the warrant may be exercised or to the exercise price of the warrant in certain events, as discussed in the section of this prospectus supplement captioned “Description of Securities We Are Offering—Warrants—Fundamental Transaction.” An adjustment which has the effect of preventing dilution is generally not a taxable event. Nevertheless, a U.S. Holder of warrants may be treated as receiving a constructive distribution from us if, for example, the adjustment increases the holder’s proportionate interest in our assets or earnings and profits (e.g., through an increase in the number of shares of common stock that would be obtained upon exercise) as a result of a distribution of cash to the holders of shares of our common stock which is taxable to such holders as a distribution. Such constructive distribution would be subject to tax in the same manner as if such U.S. Holder received a cash distribution from us (as described above under “U.S. Holders—Distributions on Our Common Stock”) equal to the fair market value of such increased interest.

Non-U.S. Holders

Allocation of Purchase Price Between Shares and Warrants

If it is relevant for a non-U.S. Holder to determine its tax basis in shares of common stock or warrants for U.S. federal income tax purposes, a non-U.S. Holder will determine such tax basis based on the allocation of the purchase price as described under “U.S. Holders—Allocation of Purchase Price Between Shares and Warrants” above.

Distributions on Our Common Stock

We have not paid and do not anticipate paying dividends. However, any dividends we pay to a non-U.S. Holder with respect to shares of our common stock will generally be subject to withholding tax at a 30% rate (or such lower rate specified by an applicable income tax treaty). To obtain the benefit of a reduced rate under an applicable income tax treaty, a non-U.S. Holder must certify as to its non-U.S. status, that no withholding is required pursuant to FATCA (discussed below), and to such right under the applicable income tax treaty on a properly completed IRS Form W-8BEN or IRS Form W-8BEN-E. If, however, a non-U.S. Holder provides an IRS Form W-8ECI, certifying that the dividend is effectively connected with the non-U.S. Holder’s conduct of a trade or business within the United States (and, in the case of certain income tax treaties, is attributable to a permanent establishment or fixed base maintained by the non-U.S. holder in the United States), the dividend will not be subject to withholding. Instead, such dividends are subject to U.S. federal income tax at regular rates applicable to United States persons generally and, for corporate holders, may also be subject to a 30% “branch profits tax” unless the non-U.S. Holder qualifies for a lower rate under an applicable U.S. income tax treaty.

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Sale, Exchange or Other Taxable Disposition of Common Stock and Warrants

A non-U.S. Holder will generally not be subject to U.S. federal income or withholding tax in respect of gain recognized on a sale, exchange or other taxable disposition of our common stock or warrants or an expiration of our warrants unless:

Gain described in the first bullet point above will be subject to tax at the generally applicable U.S. federal income tax rates. Any gains described in the first bullet point above of a non-U.S. Holder that is a foreign corporation may also be subject to an additional “branch profits tax” at a 30% rate (or lower applicable treaty rate). Gain described in the second bullet point above will generally be subject to a flat 30% U.S. federal income tax. Non-U.S. Holders are urged to consult their tax advisors regarding possible eligibility for benefits under income tax treaties. If the third bullet point above applies to a non-U.S. Holder, gain recognized by such holder on the sale, exchange or other disposition of our common stock or warrants will be subject to tax at the generally applicable U.S. federal income tax rates, and certain withholding requirements may apply. Non-U.S. Holders are urged to consult their tax advisors regarding the application of these rules.

Exercise of a Warrant

The U.S. federal income tax treatment of a non-U.S. Holder’s exercise of a warrant generally will correspond to the U.S. federal income tax treatment of the exercise of a warrant by a U.S. Holder, as described under “U.S. Holders—Exercise of a Warrant” above, although to the extent a cashless exercise results in a taxable exchange, the tax consequences to the non-U.S. Holder would be the same as those described below in “Non-U.S. Holders—Gain on Sale, Exchange or Other Taxable Disposition of Common Stock and Warrants.”

Possible Constructive Distributions

The terms of each warrant provide for an adjustment to the number of shares of common stock for which the warrant may be exercised or to the exercise price of the warrant in certain events, as discussed in the section of this prospectus captioned “Description of Securities We Are Offering —Warrants—Fundamental Transaction.” An adjustment which has the effect of preventing dilution is generally not a taxable event. Nevertheless, a non-U.S. Holder of warrants may be treated as receiving a constructive distribution from us if, for example, the adjustment increases the holder’s proportionate interest in our assets or earnings and profits (e.g., through an increase in the number of shares of common stock that would be obtained upon exercise) as a result of a distribution of cash to the holders of shares of our common stock which is taxable to such holders as a distribution. A non-U.S. Holder would be subject to U.S. federal income tax withholding in the same manner as if such non-U.S. Holder received a cash distribution from us equal to the fair market value of such increased interest.

Foreign Account Tax Compliance Act

Under the Foreign Account Tax Compliance Act (“FATCA”), withholding at a rate of 30% will generally be required on dividends in respect of shares of our common stock (or constructive dividends on our warrants) held

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by or through certain foreign financial institutions (including investment funds), unless such institution (i) enters into an agreement with the U.S. Department of the Treasury (the “Treasury”) to report, on an annual basis, information with respect to shares in, and accounts maintained by, the institution to the extent such shares (or warrants) or accounts are held by certain United States persons and by certain non-U.S. entities that are wholly or partially owned by United States persons and to withhold on certain payments, or (ii) complies with the terms of an intergovernmental agreement between the United States and an applicable foreign country. Accordingly, the entity through which our common stock or warrants is held will affect the determination of whether such withholding is required. Similarly, dividends in respect of shares of our common stock (or constructive dividends on our warrants) held by an investor that is a non-financial non-U.S. entity that does not qualify under certain exemptions will be subject to withholding at a rate of 30%, unless such entity either (i) certifies that such entity does not have any “substantial United States owners” or (ii) provides certain information regarding the entity’s “substantial United States owners,” which we or the applicable withholding agent will in turn provide to the Secretary of the Treasury. An intergovernmental agreement between the United States and an applicable foreign country, or future Treasury regulations or other guidance, may modify these requirements. We will not pay any additional amounts to investors in respect of any amounts withheld. Prospective investors are encouraged to consult their tax advisors regarding the possible implications of FATCA on their investment in our securities.

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PLAN OF DISTRIBUTION

We have arranged for the sale of the shares of our common stock and accompanying warrants we are offering pursuant to this prospectus supplement and the accompanying prospectus to the purchasers. The shares of our common stock and accompanying warrants were offered directly to the purchasers in a registered direct offering without a placement agent, underwriter, broker or dealer. The combined public offering price for each share of common stock and accompanying warrant to purchase 634,500 shares of common stock is $15.46. The warrants have an exercise price of $17.00 per share, are exercisable immediately and will expire five years from the date of issuance. We established the price of the shares of our common stock following negotiations with the purchasers and with reference to the prevailing market price of our common stock, recent trends in such price and other factors. We expect that the sale of the shares of our common stock will be completed on or around the date indicated on the cover of this prospectus supplement.

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LEGAL MATTERS

The validity of the common stock and accompanying warrants offered hereby will be passed upon for us by Skadden, Arps, Slate, Meagher & Flom LLP, Los Angeles, California.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2023 as set forth in their report, which is incorporated by reference in this prospectus supplement and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP’s report, given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3, including exhibits, under the Securities Act with respect to the securities being offered by this prospectus supplement. The registration statement, including exhibits, contains additional relevant information about us and the securities. This prospectus supplement, which constitutes part of the registration statement, does not contain all of the information set forth in the registration statement and its exhibits. For further information with respect to us and the securities offered by this prospectus supplement, we refer you to the registration statement and its exhibits. Statements contained in this prospectus supplement as to the contents of any contract or any other document referred to are not necessarily complete and, in each instance, we refer you to the copy of the contract or other document filed as an exhibit to the registration statement. Each of these statements is qualified in all respects by this reference.

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Exchange Act. Our SEC filings are available to the public at the SEC’s website at www.sec.gov.

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INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus supplement and the accompanying prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus supplement, except for any information superseded by information contained directly in this prospectus supplement, the accompanying prospectus, any subsequently filed document deemed incorporated by reference or any free writing prospectus prepared by or on behalf of us. This prospectus supplement and the accompanying prospectus incorporate by reference the documents set forth below that we have previously filed with the SEC (other than information deemed furnished and not filed in accordance with SEC rules, including Items 2.02 and 7.01 of Form 8-K).

All documents filed by us pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus supplement and before the termination of the offering also shall be deemed to be incorporated herein by reference. We are not, however, incorporating by reference any documents or portions thereof that are not deemed “filed” with the SEC, including any information furnished pursuant to Items 2.02 or 7.01 of Form 8-K.

If requested, we will provide to each person, including any beneficial owner, to whom a prospectus supplement is delivered, a copy of any or all of the information that has been incorporated by reference in the prospectus supplement but not delivered with the prospectus supplement. Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference into such documents. To obtain a copy of these filings at no cost, you may write or telephone us at the following address:

Assembly Biosciences, Inc.

Two Tower Place, 7^th Floor

South San Francisco, California 94080

Attn: Corporate Secretary

(833) 509-4584

This prospectus supplement is part of a registration statement we filed with the SEC. We have incorporated exhibits into the registration statements. You should read the exhibits carefully for provisions that may be important to you.

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Prospectus

$150,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Subscription Rights

and

Units

We may offer, issue and sell, together or separately, from time to time in one or more offerings: shares of our common stock; shares of our preferred stock, which may be issued in one or more series; debt securities, which may be issued in one or more series and which may be senior debt securities or subordinated debt securities; warrants to purchase shares of our common stock, shares of our preferred stock or our debt securities; subscription rights to purchase shares of our common stock, shares of our preferred stock or our debt securities; and/ or units. We may offer these securities separately or together in units. We will specify the terms of the securities being offered in one or more prospectus supplements and/or any related free writing prospectuses, which may also supplement, update or amend information contained or incorporated by reference in this prospectus.

The aggregate offering price of all securities sold by us under this prospectus may not exceed $150,000,000.

We will provide the specific prices and terms of these securities in one or more supplements to this prospectus at the time of offering. You should read this prospectus and the accompanying prospectus supplement carefully before you make your investment decision.

This prospectus may not be used to sell securities unless accompanied by a prospectus supplement.

Investing in our securities involves a number of risks. See “Risk Factors” on page 6 before you make your investment decision.

We may offer securities through underwriting syndicates managed or co-managed by one or more underwriters or dealers, through agents or directly to purchasers. If required, the prospectus supplement for each offering of securities will describe the plan of distribution for that offering. For general information about the distribution of securities offered, please see “Plan of Distribution” in this prospectus.

Our common stock is listed on The Nasdaq Global Select Market under the trading symbol “ASMB.” On March 21, 2023, the last reported sale price of our common stock as reported on The Nasdaq Global Select Market was $1.20 per share. Each prospectus supplement will indicate whether the securities offered thereby will be listed on any securities exchange.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus or any accompanying prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is April 14, 2023.

TABLE OF CONTENTS

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission (the “SEC”) using a “shelf” registration process. Under this shelf registration process, we may offer and sell from time to time the securities described in this prospectus in one or more offerings for an aggregate offering price of up to $150,000,000.

This prospectus only provides you with a general description of the securities that we may offer. Each time we sell securities, we will provide a supplement to this prospectus that contains specific information about the terms of that offering, including the specific amounts, prices and terms of the securities offered. The prospectus supplement may also add, update or change information contained in this prospectus. You should carefully read both this prospectus, any accompanying prospectus supplement and any free writing prospectus prepared by or on behalf of us, together with the additional information described under the heading “Where You Can Find More Information.”

We have not authorized anyone to provide you with any information other than that contained in or incorporated by reference into this prospectus, any accompanying prospectus supplement and any free writing prospectus prepared by or on behalf of us. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not making offers to sell the securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation.

The information contained in this prospectus, any prospectus supplement and any related free writing prospectus, as well as the documents incorporated by reference herein and therein is accurate only as of their respective dates (or any such earlier date as of which such information is given), regardless of the time of delivery of any such document or the time of any sale of any security. Our business, financial condition, results of operations and prospects may have changed materially since those dates.

This prospectus, any prospectus supplement and any related free writing prospectus, and the documents incorporated by reference herein and therein, may contain estimates, projections and other information concerning our industry, our business, and the markets for certain diseases, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Information that is based on estimates, forecasts, projections, market research or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained this industry, business, market and other data from reports, research surveys, studies and similar data prepared by market research firms and other third parties, industry, medical and general publications, government data and similar sources. Additionally, while such information has been obtained from sources believed to be reliable, there can be no assurance as to the accuracy or completeness of the included information. We have not independently verified any of the data from third-party sources, nor have we ascertained the underlying economic assumptions relied upon therein. While such information is believed to be reliable for the purposes used herein, none of the Company, its affiliates, nor their respective directors, officers, employees, members, partners, stockholders or agents make any representation or warranty with respect to the accuracy of such information.

The information in this prospectus is accurate as of the date on the front cover. You should not assume that the information contained in this prospectus is accurate as of any other date.

When used in this prospectus, the terms “Assembly Bio,” “Assembly,” the “Company,” “we,” “our” and “us” refer to Assembly Biosciences, Inc. and its consolidated subsidiaries, unless otherwise specified or the context otherwise requires.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Our SEC filings are available to the public at the SEC’s website at www.sec.gov.

The SEC allows us to “incorporate by reference” information into this prospectus and any accompanying prospectus supplement, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus and any accompanying prospectus supplement, except for any information superseded by information contained directly in this prospectus, any accompanying prospectus supplement, any subsequently filed document deemed incorporated by reference or any free writing prospectus prepared by or on behalf of us. This prospectus and any accompanying prospectus supplement incorporate by reference the documents set forth below that we have previously filed with the SEC (other than information deemed furnished and not filed in accordance with SEC rules, including Items 2.02 and 7.01 of Form 8-K).

All documents filed by us pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus and before the termination of the offering also shall be deemed to be incorporated herein by reference. We are not, however, incorporating by reference any documents or portions thereof that are not deemed “filed” with the SEC, including any information furnished pursuant to Items 2.02 or 7.01 of Form 8-K.

If requested, we will provide to each person, including any beneficial owner, to whom a prospectus is delivered, a copy of any or all of the information that has been incorporated by reference in the prospectus but not delivered with the prospectus. Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference into such documents. To obtain a copy of these filings at no cost, you may write or telephone us at the following address:

Assembly Biosciences, Inc.

331 Oyster Point Blvd., Fourth Floor

South San Francisco, California 94080

Attn: Corporate Secretary

(833) 509-4584

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, any applicable prospectus supplement, any related free writing prospectus and the documents that we incorporate by reference herein and therein contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the Securities Act) and Section 21E of the Securities Exchange Act of 1934, as amended (the Exchange Act). All statements other than statements of historical facts contained in this prospectus, any applicable prospectus supplement, any related free writing prospectus and any documents incorporated by reference, including statements regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward-looking statements. These statements are often, but are not always, made through the use of words or phrases such as “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will,” “would” and similar expressions, or the negative of these terms, or similar expressions. Accordingly, these statements involve estimates, assumptions and uncertainties that could cause actual results to differ materially from those expressed in them. Any forward-looking statements are qualified in their entirety by reference to the factors discussed throughout this prospectus, any applicable prospectus supplement and any related free writing prospectus, as well as the information and documents incorporated by reference herein and therein, and in particular those factors referenced in the section “Risk Factors.”

Forward-looking statements include, but are not limited to, statements about:

The forward-looking statements are based on our management’s beliefs and assumptions and on information currently available to our management. These statements involve known and unknown risks, uncertainties and other factors that may cause our actual results or events to be materially different from the plans, intentions and expectations expressed or implied by these forward-looking statements, including, without limitation the risk factors and cautionary statements described in other documents that we file from time to time with the SEC, specifically under “Item 1A: Risk Factors” and elsewhere in our Annual Report on Form 10-K for the year ended December 31, 2022 and the section of this prospectus and any applicable prospectus supplement titled “Risk Factors.”

The forward-looking statements in this prospectus, any applicable prospectus supplement and any related free writing prospectus, as well as the documents incorporated by reference herein and therein, represent our views as of their respective dates. We anticipate that subsequent events and developments will cause our views to change. However, while we may elect to update these forward-looking statements at some point in the future, we assume no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law. You should, therefore, not rely on these forward-looking statements as representing our views as of any date subsequent to the dates on which they were made.

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THE COMPANY

We are a biopharmaceutical company advancing clinical candidates with the potential to improve the lives of millions of people living with chronic hepatitis B virus (“HBV”) infection around the world, an early stage development program targeting high-recurrence genital herpes associated with herpes simplex virus type 2 (HSV-2) and research programs focused on the discovery of novel antivirals to treat devastating viral diseases, including hepatitis delta virus (“HDV”) and transplant-related herpesviruses.

Our current business strategy is focused on three parallel paths:

HBV

Inspired by the hundreds of millions of people worldwide living with chronic HBV infection, the goal of our HBV program is to discover and develop finite and curative therapies for these patients. While we have learned that combination therapy with our first-generation CI product candidate, vebicorvir (“VBR”) plus the standard of care, nucleos(t)ide analog reverse transcriptase inhibitor (“NrtI”), did not result in a finite and curative treatment, we have designed and developed our next generation CIs for significantly increased potency and ability to engage an additional mechanism of action, targeting the viral reservoir, that VBR could not. We believe that a regimen of our next generation CIs in combination with NrtI therapy will be the antiviral backbone of future finite and curative therapies. To reach a finite and curative therapy, it may also be necessary to include additional mechanisms of action, whether discovered and developed internally or externally through collaborations, licenses, partnerships and other types of business arrangements.

Development Pipeline

To complement our CI programs seeking finite and curative chronic HBV therapies, we have leveraged the depth and breadth of our virology expertise to expand our pipeline with a focus on novel mechanisms acting on clinically validated targets in therapeutic areas of high unmet medical need. Since beginning this expansion of our portfolio in late 2021, we have announced several new programs, both in- and outside of HBV: our HDV/HBV entry inhibitor program, our IFNAR agonist program, our pan-herpes NNPI program for transplant-associated infections and the long-acting HSV-2 helicase inhibitor for high-recurrence genital herpes. We recently nominated 5366 as a development candidate for our HSV-2 program and look forward to future candidate nominations from our discovery virology pipeline.

We believe that these new programs are compelling complements to our CIs, as each program focuses on a clinically validated target in a virologic disease where innovation is critical to improving patients’ lives. In addition, because our new programs are focused on treatments for chronic diseases, rather than curative therapies, the path to proof-of-concept and registrational studies may be significantly shorter than that for our finite and curative HBV therapeutics.

We currently have corporate and administrative offices and research laboratory space in South San Francisco, California as well as registrational offices in China.

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Assembly Biosciences, Inc., formerly known as Ventrus BioSciences, Inc., was incorporated under the laws of the State of Delaware on October 7, 2005, originally under the name South Island Biosciences, Inc. On July 11, 2014, we acquired Assembly Pharmaceuticals, Inc., a private company (the Merger). In connection with the Merger, we changed our name from Ventrus Biosciences, Inc. to Assembly Biosciences, Inc.

Our principal executive office is located at 331 Oyster Point Blvd., Fourth Floor, South San Francisco, California 94080 and our telephone number is (833) 509-4583. We maintain a website at www.assemblybio.com. The information on our website is not incorporated by reference in this prospectus or any accompanying prospectus supplement, and you should not consider it a part of this prospectus or any accompanying prospectus supplement.

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RISK FACTORS

Investing in our securities involves risk. See the risk factors described in our most recent Annual Report on Form 10-K (together with any material changes thereto contained in subsequent filings with the SEC that are incorporated by reference in this prospectus and any accompanying prospectus supplement) and those contained in our other filings with the SEC that are incorporated by reference in this prospectus and any accompanying prospectus supplement. Before making an investment decision, you should carefully consider these risks as well as other information we include or incorporate by reference in this prospectus and any accompanying prospectus supplement. These risks could materially affect our business, financial condition or results of operations and cause the value of our securities to decline. You could lose all or part of your investment.

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USE OF PROCEEDS

Except as otherwise set forth in any accompanying prospectus supplement, we expect to use the net proceeds from the sale of securities for general corporate purposes, including the financing of our operations, the possible repayment of indebtedness, if applicable, and possible business acquisitions.

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DESCRIPTION OF SECURITIES

This prospectus contains summary descriptions of the common stock, preferred stock, debt securities, warrants and subscription rights that may be offered and sold from time to time. These summary descriptions are not meant to be complete descriptions of each security. However, at the time of an offering and sale, this prospectus together with the accompanying prospectus supplement will contain the material terms of the securities being offered.

DESCRIPTION OF CAPITAL STOCK

General

The following summary description of our capital stock is based on the provisions of the Delaware General Corporation Law (the “DGCL”), our certificate of incorporation, as amended, and our bylaws, as amended. This description does not purport to be complete and is qualified in its entirety by reference to the full text of the DGCL, as it may be amended from time to time, and to the terms of our certificate of incorporation and bylaws, as each may be amended from time to time, which are incorporated by reference as exhibits to the registration statement of which this prospectus is a part. See “Where You Can Find More Information.” As used in this “Description of Capital Stock,” the terms “Assembly Bio,” “Assembly,” the “Company,” “we,” “our” and “us” refer to Assembly Biosciences, Inc., a Delaware corporation, and do not, unless otherwise specified, include our subsidiaries.

Authorized Capital Stock

Our authorized capital stock consists of 150,000,000 shares of common stock, par value $0.001 per share, and 5,000,000 shares of preferred stock, par value $0.001 per share. The number of authorized shares of any class may be increased or decreased by an amendment to our certificate of incorporation proposed by our board of directors and approved by a majority of outstanding shares voted on the issue at a meeting at which a quorum exists.

Common Stock

The holders of our common stock are entitled to one vote per share on all matters to be voted on by the stockholders, and there are no cumulative voting rights.

The holders of common stock are entitled to receive ratable dividends, if any, payable when and as declared by our board of directors or any authorized committee thereof out of assets or funds legally available therefor, subject to any preferential rights that may be applicable to any outstanding preferred stock. In the event of a liquidation, dissolution or winding up of our company, after payment in full of all outstanding debts and other liabilities, the holders of common stock are entitled to share ratably in all remaining assets, subject to prior distribution rights of preferred stock, if any, then outstanding. No shares of common stock have preemptive rights or other subscription rights to purchase additional shares of common stock. There are no redemption or sinking fund provisions applicable to the common stock.

Preferred Stock

Our board of directors is authorized to issue up to 5,000,000 shares of preferred stock in one or more series without stockholder approval. Our board of directors may determine the rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, of each series of preferred stock. The purpose of authorizing our board of directors to issue preferred stock in one or more series and determine the number of shares in the series and its rights and preferences is to

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eliminate delays associated with a stockholder vote on specific issuances. The existence of authorized but unissued shares of preferred stock may enable our board of directors to render more difficult or to discourage an attempt to obtain control of us by means of a merger, tender offer, proxy contest or otherwise. The rights of holders of our common stock described above will be subject to, and may be adversely affected by, the rights of any preferred stock that we may designate and issue in the future. The issuance of shares of preferred stock could decrease the amount of earnings and assets available for distribution to holders of shares of common stock. The issuance may also adversely affect the rights and powers, including voting rights, of these holders and may have the effect of delaying, deterring or preventing a change in control of us.

We will incorporate by reference as an exhibit to the registration statement of which this prospectus forms a part the form of any certificate of designation that describes the terms of any series of preferred stock we may offer. This description and the applicable prospectus supplement and/or any related free writing prospectus may include the following terms, among others, where applicable:

When we issue shares of preferred stock under this prospectus, the shares will fully be paid and nonassessable and will not have, or be subject to, any preemptive or similar rights.

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Anti-Takeover Effects of Provisions of the Certificate of Incorporation, Bylaws and Other Agreements

Certain provisions of the DGCL, our certificate of incorporation and our bylaws could have the effect of delaying, deferring or discouraging another party from acquiring control of us. These provisions, which are summarized below, are expected to discourage certain types of coercive takeover practices and inadequate takeover bids and, as a consequence, they might also inhibit temporary fluctuations in the market price of our common stock that often result from actual or rumored hostile takeover attempts. These provisions are also designed in part to encourage anyone seeking to acquire control of us or considering unsolicited tender offers or other unilateral takeover proposals to first negotiate with our board of directors rather than pursue non-negotiated takeover attempts. These provisions might also have the effect of preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish transactions that stockholders might otherwise deem to be in their best interests. However, we believe that the advantages gained by protecting our ability to negotiate with any unsolicited and potentially unfriendly acquirer outweigh the disadvantages of discouraging such proposals, including those priced above the then-current market value of our common stock, because, among other reasons, the negotiation of such proposals could improve their terms.

Delaware Antitakeover Law

We are subject to the provisions of Section 203 of the DGCL (Section 203). In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a three-year period following the time that this stockholder becomes an interested stockholder, unless the business combination is approved in a prescribed manner. A “business combination” includes, among other things, a merger, asset or stock sale or other transaction resulting in a financial benefit to the interested stockholder. An “interested stockholder” is a person who, together with such person’s affiliates and associates, owns, or did own within three years prior to such determination, 15% or more of the corporation’s voting stock. Under Section 203, a business combination between a corporation and an interested stockholder is prohibited unless it satisfies one of the following conditions:

Charter Documents

Our certificate of incorporation and our bylaws include a number of provisions that may have the effect of deterring hostile takeovers or delaying or preventing changes in control or management of our company. First, our certificate of incorporation and our bylaws provide that all stockholder action must be effected at a duly called meeting of stockholders and not by a consent in writing. Further, our bylaws limit who may call special meetings of the stockholders. Our certificate of incorporation does not include a provision for cumulative voting for directors. Under cumulative voting, a minority stockholder holding a sufficient percentage of a class of shares may be able to ensure the election of one or more directors. Our bylaws provide that the number of directors on our board, which may range from three to ten directors, shall be exclusively fixed by our board, which has set the number of directors at seven. Newly created directorships resulting from any increase in our authorized number

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of directors and any vacancies in our board resulting from death, resignation, retirement, disqualification or other cause (including removal from office by a vote of the stockholders) will be filled by a majority of our board then in office. Finally, our bylaws establish procedures and other terms and conditions, including advance notice procedures, regarding special meeting requests by stockholders holding in the aggregate at least 25% of our outstanding common stock, nomination of candidates for election as directors and stockholder proposals. These and other provisions of our certificate of incorporation, our bylaws and Delaware law could discourage potential acquisition proposals and could delay or prevent a change in control or management of our company.

Our bylaws also provide that the Court of Chancery of the State of Delaware (or if such court does not have jurisdiction, the Superior Court of Delaware, or if such other court does not have jurisdiction, the United States District Court for the District of Delaware) will be the exclusive forum for: any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the DGCL, our certificate of incorporation or our bylaws; or any action asserting a claim against us that is governed by the internal affairs doctrine. This provision will not apply to litigation brought to enforce any liability or duty created by: the Securities Act of 1933, as amended; the Securities Exchange Act of 1934, as amended; or the rules and regulations thereunder. The enforceability of similar choice of forum provisions in other companies’ organizational documents has been challenged in legal proceedings and, while the Delaware Supreme Court has upheld the validity of certain choice of forum provisions, it is possible that, in connection with one or more actions or proceedings described above, a court could find the choice of forum provisions contained in our bylaws to be inapplicable or unenforceable.

Listing

Our common stock is listed on The Nasdaq Global Select Market under the symbol “ASMB.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company, LLC. The transfer agent and registrar’s address is 6201 15th Avenue, Brooklyn, New York 11219.

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DESCRIPTION OF DEBT SECURITIES

The paragraphs below describe the general terms and provisions of the debt securities we may issue. When we offer to sell a particular series of debt securities, we will describe the specific terms of such series, including any additional covenants or other terms or changes to existing covenants or other terms relating to such series, in a prospectus supplement and/or any related free writing prospectus. The prospectus supplement and/or any related free writing prospectus will also indicate whether the general terms and provisions described in this prospectus apply to a particular series of debt securities. We urge you to read any prospectus supplement and/or any related free writing prospectus related to any series of debt securities we may offer under this prospectus, as well as the actual indenture and any related supplemental indenture or officer’s certificate containing the terms of the debt securities.

We may offer senior or subordinated debt securities. Each series of debt securities may have different terms. The senior debt securities will be issued under one or more senior indentures, dated as of a date on or prior to such issuance, between us and the trustee identified in the applicable prospectus supplement and/or any related free writing prospectus, each as amended or supplemented from time to time. We will refer to any such indenture throughout this prospectus as the “senior indenture.” Any subordinated debt securities will be issued under one or more indentures, dated as of a date on or prior to such issuance, between us and the trustee identified in the applicable prospectus supplement and/or any related free writing prospectus, each as amended or supplemented from time to time. We will refer to any such indenture throughout this prospectus as the “subordinated indenture.” We will refer to the trustee under the senior indenture or the subordinated indenture as the “trustee.” The senior indenture and the subordinated indenture are sometimes collectively referred to in this prospectus as the “indentures.” The indentures will be subject to and governed by the Trust Indenture Act of 1939, as amended (the Trust Indenture Act). We have included copies of the forms of the indentures as exhibits to our registration statement of which this prospectus forms a part, however such forms will be amended and supplemented or replaced by one or more supplemental indentures or officer’s certificates or otherwise with respect to the specific terms of any series of debt securities we may offer.

If we issue debt securities at a discount from their principal amount, then, for purposes of calculating the aggregate offering price of the offered securities issued under this prospectus, we will include only the offering price of the debt securities and not the principal amount of the debt securities.

We have summarized below the material provisions of the indentures and the debt securities, or indicated which material provisions will be described in a prospectus supplement and/or any related free writing prospectus. The prospectus supplement and/or any related free writing prospectus relating to any particular securities offered will describe the specific terms of the securities, which may be in addition to or different from the general terms summarized in this prospectus. Because the summary in this prospectus and in any prospectus supplement and/or any related free writing prospectus does not contain all of the information that you may find useful, you should read the documents relating to the securities that are described in this prospectus or in any applicable prospectus supplement and/or any related free writing prospectus. Please read “Where You Can Find More Information” to find out how you can obtain a copy of those documents. Except as otherwise indicated, the terms of the indentures are identical. As used under this caption, the term “debt securities” includes the debt securities being offered by this prospectus and all other debt securities that may be issued by us under the indentures.

General

The indentures:

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Unless we give you different information in the applicable prospectus supplement and/or any related free writing prospectus, the senior debt securities will be unsubordinated obligations and will be equal in right of payment with all of our other unsecured and unsubordinated indebtedness (if any). Payments on the subordinated debt securities will be subordinated in right of payment to the prior payment in full of all of our senior indebtedness, as described under “—Subordination” and in the applicable prospectus supplement and/or any related free writing prospectus.

Each indenture provides that we may, but need not, designate more than one trustee under an indenture. Any trustee under an indenture may resign or be removed and a successor trustee may be appointed to act with respect to the series of debt securities administered by the resigning or removed trustee. If two or more persons are acting as trustee with respect to different series of debt securities, each trustee shall be a trustee of a trust under the applicable indenture separate and apart from the trust administered by any other trustee. Except as otherwise indicated in this prospectus, any action described in this prospectus to be taken by each trustee may be taken by each trustee with respect to, and only with respect to, the one or more series of debt securities for which it is trustee under the applicable indenture.

The prospectus supplement and/or any related free writing prospectus for each offering may include the following terms, among others, where applicable:

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We may issue debt securities that provide for less than the entire principal amount thereof to be payable upon declaration of acceleration of the maturity of the debt securities. We refer to any such debt securities throughout this prospectus as “original issue discount securities.” The applicable prospectus supplement and/or any related free writing prospectus will describe the U.S. federal income tax consequences and other relevant considerations applicable to original issue discount securities.

We also may issue indexed debt securities. Payments of principal of, and premium and interest on, indexed debt securities are determined with reference to the rate of exchange between the currency or currency unit in which the debt security is denominated and any other currency or currency unit specified by us, to the relationship between two or more currencies or currency units or by other similar methods or formulas specified in the prospectus supplement and/or any related free writing prospectus.

Except as described under “—Merger, Consolidation or Sale of Assets” or as may be set forth in any prospectus supplement and/or any related free writing prospectus, the debt securities will not contain any provisions that would (1) limit our ability to incur indebtedness or (2) afford holders of debt securities protection in the event of (a) a highly leveraged or similar transaction involving us or (b) a change of control or reorganization, restructuring, merger or similar transaction involving us that may adversely affect the holders of the debt securities. In the future, we may enter into transactions, such as the sale of all or substantially all of our assets or a merger or consolidation, that may have an adverse effect on our ability to service our indebtedness, including the debt securities, by, among other things, substantially reducing or eliminating our assets.

Our governing instruments do not define the term “substantially all” as it relates to the sale of assets. Additionally, case law interpreting the term “substantially all” relies upon the facts and circumstances of each particular case. Consequently, to determine whether a sale of “substantially all” of our assets has occurred, a holder of debt securities must review the financial and other information that we have disclosed to the public.

We will provide you with more information in the applicable prospectus supplement and/or any related free writing prospectus regarding any deletions, modifications or additions to the events of default or covenants or other terms that are described above or below.

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Payment

Unless we give you different information in the applicable prospectus supplement and/or any related free writing prospectus, the principal of, and any premium or make-whole amount, and interest on, any series of the debt securities will be payable at the corporate trust office of the trustee. We will provide you with the address of the trustee in the applicable prospectus supplement and/or any related free writing prospectus. We may also pay interest by mailing a check to the address of the person entitled to it as it appears in the applicable register for the debt securities or by wire transfer of funds to that person at an account maintained within the United States or in accordance with the applicable procedures of the Depository Trust Company (DTC) or any other applicable depository company.

All monies that we pay to a paying agent or a trustee for the payment of the principal of, and any premium or make-whole amount, or interest on, any debt security will be repaid to us if unclaimed at the end of two years after the obligation underlying payment becomes due and payable. After funds have been returned to us, the holder of the debt security may look only to us for payment, without payment of interest for the period which we hold the funds.

Denomination, Interest, Registration and Transfer

Unless otherwise described in the applicable prospectus supplement and/or any related free writing prospectus, the debt securities of any series will be issuable in a minimum denomination of $1,000 and integral multiples of $1,000.

Subject to the limitations imposed upon debt securities that are evidenced by a book-entry position in the records of DTC or another depository company rather than by physical delivery of a note, a holder of debt securities of any series may:

Every debt security surrendered for registration of transfer or exchange must be duly endorsed or accompanied by a written instrument of transfer satisfactory to the applicable trustee or transfer agent or, as applicable, comply with the applicable procedures of DTC or another depository company. Payment of a service charge will not be required for any registration of transfer or exchange of any debt securities, but we or the trustee may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. If in addition to the applicable trustee, the applicable prospectus supplement and/or any related free writing prospectus refers to any transfer agent initially designated by us for any series of debt securities, we may at any time rescind the designation of any such transfer agent or approve a change in the location through which any such transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for such series. We may at any time designate additional transfer agents for any series of debt securities.

Neither we, nor any trustee, will be required to:

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Merger, Consolidation or Sale of Assets

The indentures provide that we may, without the consent of the holders of any outstanding debt securities, (1) consolidate with, (2) sell, lease or convey all or substantially all of our assets to or (3) merge with or into any other entity, provided that:

Covenants

Existence

Except as described under “—Merger, Consolidation or Sale of Assets,” the indentures require us to do or cause to be done all things necessary to preserve and keep in full force and effect our existence, rights and franchises. However, the indentures do not require us to preserve any right or franchise if we determine that any right or franchise is no longer desirable in the conduct of our business.

Payment of Taxes and Other Claims

The indentures require us to pay, discharge or cause to be paid or discharged, before they become delinquent, (1) all taxes, assessments and governmental charges levied or imposed on us and (2) all lawful claims for labor, materials and supplies which, if unpaid, might by law become a lien upon our property. However, we will not be required to pay, discharge or cause to be paid or discharged any such tax, assessment, charge or claim whose amount, applicability or validity is being contested in good faith by appropriate proceedings.

Provision of Financial Information

The indentures require us to (1) within 15 days of each of the respective dates by which we are required to file our annual reports, quarterly reports and other documents with the SEC, file with the trustee copies of the annual report, quarterly report and other documents that we file with the SEC under Section 13 or 15(d) of the Exchange Act, (2) file with the trustee and the SEC any additional information, documents and reports regarding compliance by us with the conditions and covenants of the indentures, as required, (3) within 30 days after the filing with the trustee, mail to all holders of debt securities, as their names and addresses appear in the applicable register for such debt securities, without cost to such holders, summaries of any documents and reports required to be filed by us pursuant to (1) and (2) above, and (4) supply, promptly upon written request and payment of the reasonable cost of duplication and delivery, copies of such documents to any prospective holder of debt securities.

Additional Covenants

The applicable prospectus supplement and/or any related free writing prospectus will set forth any of our additional covenants relating to any series of debt securities.

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Events of Default, Notice and Waiver

Unless the applicable prospectus supplement and/or any related free writing prospectus states otherwise, when we refer to “events of default” as defined in the indentures with respect to any series of debt securities, we mean:

If an event of default occurs and is continuing with respect to debt securities of any series outstanding, then the applicable trustee or the holders of 25% or more in principal amount of the debt securities of that series will have the right to declare the principal amount of all the debt securities of that series to be due and payable. If the debt securities of that series are original issue discount securities or indexed securities, then the applicable trustee or the holders of 25% or more in principal amount of the debt securities of that series will have the right to declare the portion of the principal amount as may be specified in the terms thereof to be due and payable. However, at any time after such a declaration of acceleration has been made, but before a judgment or decree for payment of the money due has been obtained by the applicable trustee, the holders of at least a majority in principal amount of outstanding debt securities of such series or of all debt securities then outstanding under the applicable indenture may rescind and annul such declaration and its consequences if:

The indentures also provide that the holders of at least a majority in principal amount of the outstanding debt securities of any series or of all debt securities then outstanding under the applicable indenture may, on behalf of all holders, waive any past default with respect to such series and its consequences, except a default:

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The indentures require each trustee to give notice to the holders of debt securities within 90 days of a default unless such default has been cured or waived. However, the trustee may withhold notice if specified persons of such trustee consider such withholding to be in the interest of the holders of debt securities. The trustee may not withhold notice of a default in the payment of principal, any premium or interest on any debt security of such series or in the payment of any sinking fund installment in respect of any debt security of such series.

The indentures provide that holders of debt securities of any series may not institute any proceedings, judicial or otherwise, with respect to such indenture or for any remedy under the indenture, unless the trustee fails to act for a period of 60 days after the trustee has received a written request to institute proceedings in respect of an event of default from the holders of 25% or more in principal amount of the outstanding debt securities of such series, as well as an offer of indemnity reasonably satisfactory to the trustee. However, this provision will not prevent any holder of debt securities from instituting suit for the enforcement of payment of the principal of, and any premium or make-whole amount, and interest on, such debt securities at the respective due dates thereof.

The indentures provide that, subject to provisions in each indenture relating to its duties in the case of a default, a trustee has no obligation to exercise any of its rights or powers at the request or direction of any holders of any series of debt securities then outstanding under the indenture, unless the holders have offered to the trustee reasonable security or indemnity. The holders of at least a majority in principal amount of the outstanding debt securities of any series or of all debt securities then outstanding under an indenture shall have the right to direct the time, method and place of conducting any proceeding for any remedy available to the applicable trustee, or of exercising any trust or power conferred upon such trustee. However, a trustee may refuse to follow any direction which:

Within 120 days after the close of each fiscal year, we will be required to deliver to each trustee a certificate, signed by one of our several specified officers, stating whether or not such officer has knowledge of any default under the applicable indenture. If the officer has knowledge of any default, the notice must specify the nature and status of the default.

Modification of the Indentures

The indentures provide that modifications and amendments may be made only with the consent of the affected holders of a majority in principal amount of all outstanding debt securities issued under that indenture. However, no such modification or amendment may, without the consent of the holders of the debt securities affected by the modification or amendment:

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The holders of a majority in aggregate principal amount of the outstanding debt securities of each series may, on behalf of all holders of debt securities of that series, waive, insofar as that series is concerned, our compliance with material restrictive covenants of the applicable indenture.

We and the respective trustee may make modifications and amendments of an indenture without the consent of any holder of debt securities for any of the following purposes:

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Voting

The indentures provide that in determining whether the holders of the requisite principal amount of outstanding debt securities of a series have given any request, demand, authorization, direction, notice, consent or waiver under the indentures or whether a quorum is present at a meeting of holders of debt securities:

The indentures contain provisions for convening meetings of the holders of debt securities of a series. A meeting will be permitted to be called at any time by the applicable trustee, and also, upon request, by us or the holders of at least 25% in principal amount of the outstanding debt securities of such series, in any such case upon notice given as provided in such indenture. Except for any consent that must be given by the holder of each debt security affected by the modifications and amendments of an indenture described above, any resolution presented at a meeting or adjourned meeting duly reconvened at which a quorum is present may be adopted by the affirmative vote of the holders of a majority of the aggregate principal amount of the outstanding debt securities of that series represented at such meeting.

Notwithstanding the preceding paragraph, except as referred to above, any resolution relating to a request, demand, authorization, direction, notice, consent, waiver or other action that may be made, given or taken by the holders of a specified percentage, which is less than a majority of the aggregate principal amount of the outstanding debt securities of a series, may be adopted at a meeting or adjourned meeting duly reconvened at which a quorum is present by the affirmative vote of such specified percentage.

Any resolution passed or decision taken at any properly held meeting of holders of debt securities of any series will be binding on all holders of such series. The quorum at any meeting called to adopt a resolution, and at any reconvened meeting, will be persons holding or representing a majority in principal amount of the outstanding debt securities of a series. However, if any action is to be taken relating to a consent or waiver that may be given by the holders of at least a specified percentage in principal amount of the outstanding debt securities of a series, the persons holding such percentage will constitute a quorum.

Notwithstanding the foregoing provisions, the indentures provide that if any action is to be taken at a meeting with respect to any request, demand, authorization, direction, notice, consent, waiver or other action that such indenture expressly provides may be made, given or taken by the holders of a specified percentage in principal amount of all outstanding debt securities affected by such action, or of the holders of such series and one or more additional series:

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Subordination

Unless otherwise provided in the applicable prospectus supplement and/or related free writing prospectus, subordinated debt securities will be subject to the following subordination provisions.

Upon any distribution to our creditors in a liquidation, dissolution or reorganization, the payment of the principal of and interest on any subordinated debt securities will be subordinated to the extent provided in the applicable indenture in right of payment to the prior payment in full of all senior debt. However, our obligation to make payments of the principal of and interest on such subordinated debt securities otherwise will not be affected. No payment of principal or interest will be permitted to be made on subordinated debt securities at any time if a default on senior debt exists that permits the holders of such senior debt to accelerate its maturity and the default is the subject of judicial proceedings or we receive notice of the default. After all senior debt is paid in full and until the subordinated debt securities are paid in full, holders of subordinated debt securities will be subrogated to the rights of holders of senior debt to the extent that distributions otherwise payable to holders of subordinated debt securities have been applied to the payment of senior debt. The subordinated indenture will not restrict the amount of senior debt or other indebtedness of ours. As a result of these subordination provisions, in the event of a distribution of assets upon insolvency, holders of subordinated debt securities may recover less, ratably, than our general creditors.

The term “senior debt” will be defined in the applicable indenture as the principal of and interest on, or substantially similar payments to be made by us in respect of, other outstanding indebtedness, whether outstanding at the date of execution of the applicable indenture or subsequently incurred, created or assumed. The prospectus supplement and/or related free writing prospectus may include a description of additional terms implementing the subordination feature.

No restrictions will be included in any indenture relating to subordinated debt securities upon the creation of additional senior debt.

If this prospectus is being delivered in connection with the offering of a series of subordinated debt securities, the accompanying prospectus supplement and/or any related free writing prospectus or the information incorporated herein by reference will set forth the approximate amount of senior debt outstanding as of the end of our most recent fiscal quarter.

Discharge, Defeasance and Covenant Defeasance

Unless otherwise indicated in the applicable prospectus supplement and/or any related free writing prospectus, the indentures allow us to discharge our obligations to holders of any series of debt securities issued under any indenture when:

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Unless otherwise indicated in the applicable prospectus supplement and/or related free writing prospectus, the indentures provide that, upon our irrevocable deposit with the applicable trustee, in trust, of an amount, in such currency or currencies, currency unit or units or composite currency or currencies in which such debt securities are payable at stated maturity, or government obligations, or both, applicable to such debt securities, which through the scheduled payment of principal and interest in accordance with their terms will provide money in an amount sufficient to pay the principal of, and any premium or make-whole amount, and interest on, such debt securities, and any mandatory sinking fund or analogous payments thereon, on the scheduled due dates therefor, the issuing company may elect either:

Notwithstanding the above, we may not elect to defease and be discharged from the obligation to pay any additional amounts upon the occurrence of particular events of tax, assessment or governmental charge with respect to payments on such debt securities and the obligations to register the transfer or exchange of such debt securities, to replace temporary or mutilated, destroyed, lost or stolen debt securities, to maintain an office or agency in respect of such debt securities, or to hold monies for payment in trust.

The indentures only permit us to establish the trust described in the paragraph above if, among other things, we have delivered to the applicable trustee an opinion of counsel to the effect that the holders of such debt securities will not recognize income, gain or loss for United States federal income tax purposes as a result of such defeasance or covenant defeasance and will be subject to U.S. federal income tax on the same amounts, in the same manner and at the same times as would have been the case if such defeasance or covenant defeasance had not occurred. Such opinion of counsel, in the case of defeasance, will be required to refer to and be based upon a ruling received from or published by the Internal Revenue Service or a change in applicable U.S. federal income tax law occurring after the date of the indenture. In the event of such defeasance, the holders of such debt securities would be able to look only to such trust fund for payment of principal, any premium or make-whole amount, and interest.

When we use the term “government obligations,” we mean securities that are:

Unless otherwise provided in the applicable prospectus supplement and/or any related free writing prospectus, if after we have deposited funds and/or government obligations to effect defeasance or covenant defeasance with respect to debt securities of any series, (1) the holder of a debt security of such series is entitled to, and does,

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elect under the terms of the applicable indenture or the terms of such debt security to receive payment in a currency, currency unit or composite currency other than that in which such deposit has been made in respect of such debt security or (2) a conversion event occurs in respect of the currency, currency unit or composite currency in which such deposit has been made, the indebtedness represented by such debt security will be deemed to have been, and will be, fully discharged and satisfied through the payment of the principal of, and premium or make-whole amount, and interest on, such debt security as they become due out of the proceeds yielded by converting the amount so deposited in respect of such debt security into the currency, currency unit or composite currency in which such debt security becomes payable as a result of such election or such cessation of usage based on the applicable market exchange rate.

When we use the term “conversion event,” we mean the cessation of use of:

Unless otherwise provided in the applicable prospectus supplement and/or related free writing prospectus, all payments of principal of, and any premium or make-whole amount, and interest on, any debt security that is payable in a foreign currency that ceases to be used by its government of issuance shall be made in U.S. dollars.

In the event that (1) we effect covenant defeasance with respect to any debt securities and (2) those debt securities are declared due and payable because of the occurrence of any event of default, the amount in the currency, currency unit or composite currency in which such debt securities are payable, and government obligations on deposit with the applicable trustee, will be sufficient to pay amounts due on such debt securities at the time of their stated maturity but may not be sufficient to pay amounts due on such debt securities at the time of the acceleration resulting from such event of default. However, the issuing company would remain liable to make payments of any amounts due at the time of acceleration.

The applicable prospectus supplement and/or any related free writing prospectus may further describe the provisions, if any, permitting such defeasance or covenant defeasance, including any modifications to the provisions described above, with respect to the debt securities of or within a particular series.

Conversion Rights

The terms and conditions, if any, upon which the debt securities are convertible into common stock or other securities of ours will be set forth in the applicable prospectus supplement and/or related free writing prospectus. The terms will include whether the debt securities are convertible into shares of common stock or other securities of ours, the conversion price, or manner of calculation thereof, the conversion period, provisions as to whether conversion will be at the issuing company’s option or the option of the holders, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption of the debt securities and any restrictions on conversion.

Global Securities

The debt securities of a series may be issued in whole or in part in the form of one or more global securities that will be deposited with, or on behalf of, a depository identified in the applicable prospectus supplement and/or any related free writing prospectus relating to such series. Global securities, if any, issued in the United States are

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expected to be deposited with DTC as depository. We may issue global securities in either registered or bearer form and in either temporary or permanent form. We will describe the specific terms of the depository arrangement with respect to a series of debt securities in the applicable prospectus supplement and/or any related free writing prospectus relating to such series. We expect that unless the applicable prospectus supplement and/or related free writing prospectus provides otherwise, the following provisions will apply to depository arrangements.

Once a global security is issued, the depository for such global security or its nominee will credit on its book-entry registration and transfer system the respective principal amounts of the individual debt securities represented by such global security to the accounts of participants that have accounts with such depository. Such accounts shall be designated by the underwriters, dealers or agents with respect to such debt securities or by us if we offer such debt securities directly. Ownership of beneficial interests in such global security will be limited to participants with the depository or persons that may hold interests through those participants.

We expect that, under procedures established by DTC, ownership of beneficial interests in any global security for which DTC is the depository will be shown on, and the transfer of that ownership will be effected only through, records maintained by DTC or its nominee, with respect to beneficial interests of participants with the depository, and records of participants, with respect to beneficial interests of persons who hold through participants with the depository. Neither we nor the trustee will have any responsibility or liability for any aspect of the records of DTC or for maintaining, supervising or reviewing any records of DTC or any of its participants relating to beneficial ownership interests in the debt securities. The laws of some states require that certain purchasers of securities take physical delivery of such securities in definitive form. Such limits and laws may impair the ability to own, pledge or transfer beneficial interest in a global security.

So long as the depository for a global security or its nominee is the registered owner of such global security, such depository or such nominee, as the case may be, will be considered the sole owner or holder of the debt securities represented by the global security for all purposes under the applicable indenture. Except as described below or in the applicable prospectus supplement and/or any related free writing prospectus, owners of beneficial interest in a global security will not be entitled to have any of the individual debt securities represented by such global security registered in their names, will not receive or be entitled to receive physical delivery of any such debt securities in definitive form and will not be considered the owners or holders thereof under the applicable indenture. Beneficial owners of debt securities evidenced by a global security will not be considered the owners or holders thereof under the applicable indenture for any purpose, including with respect to the giving of any direction, instructions or approvals to the trustee under the indenture. Accordingly, each person owning a beneficial interest in a global security with respect to which DTC is the depository must rely on the procedures of DTC and, if such person is not a participant with the depository, on the procedures of the participant through which such person owns its interests, to exercise any rights of a holder under the applicable indenture. We understand that, under existing industry practice, if DTC requests any action of holders or if an owner of a beneficial interest in a global security desires to give or take any action which a holder is entitled to give or take under the applicable indenture, DTC would authorize the participants holding the relevant beneficial interest to give or take such action, and such participants would authorize beneficial owners through such participants to give or take such actions or would otherwise act upon the instructions of beneficial owners holding through them.

Payments of principal of, and any premium or make-whole amount, and interest on, individual debt securities represented by a global security registered in the name of a depository or its nominee will be made to or at the direction of the depository or its nominee, as the case may be, as the registered owner of the global security under the applicable indenture. Under the terms of the applicable indenture, we and the trustee may treat the persons in whose name debt securities, including a global security, are registered as the owners thereof for the purpose of receiving such payments. Consequently, neither we nor the trustee have or will have any responsibility or liability for the payment of such amounts to beneficial owners of debt securities including principal, any premium or make-whole amount, or interest. We believe, however, that it is currently the policy of DTC to immediately credit the accounts of relevant participants with such payments, in amounts proportionate to their

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respective holdings of beneficial interests in the relevant global security as shown on the records of DTC or its nominee. We also expect that payments by participants to owners of beneficial interests in such global security held through such participants will be governed by standing instructions and customary practices, as is the case with securities held for the account of customers in bearer form or registered in street name, and will be the responsibility of such participants. Redemption notices with respect to any debt securities represented by a global security will be sent to the depository or its nominee. If less than all of the debt securities of any series are to be redeemed, we expect the depository to determine the amount of the interest of each participant in such debt securities to be redeemed to be determined by lot. Neither we, the trustee, any paying agent nor the security registrar for such debt securities will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in the global security for such debt securities or for maintaining any records with respect thereto.

Neither we nor the trustee will be liable for any delay by the holders of a global security or the depository in identifying the beneficial owners of debt securities, and we and the trustee may conclusively rely on, and will be protected in relying on, instructions from the holder of a global security or the depository for all purposes. The rules applicable to DTC and its participants are on file with the SEC.

If a depository for any debt securities is at any time unwilling, unable or ineligible to continue as depository and we do not appoint a successor depository within 90 days, we will issue individual debt securities in exchange for the global security representing such debt securities. In addition, we may at any time and at our sole discretion, subject to any limitations described in the applicable prospectus supplement and/or any related free writing prospectus relating to such debt securities, determine not to have any of such debt securities represented by one or more global securities and in such event will issue individual debt securities in exchange for the global security or securities representing such debt securities. Individual debt securities so issued will be issued in denominations of $1,000 and integral multiples of $1,000.

The debt securities of a series may also be issued in whole or in part in the form of one or more bearer global securities that will be deposited with a depository, or with a nominee for such depository, identified in the applicable prospectus supplement and/or any related free writing prospectus. Any such bearer global securities may be issued in temporary or permanent form. The specific terms and procedures, including the specific terms of the depositary arrangement, with respect to any portion of a series of debt securities to be represented by one or more bearer global securities will be described in the applicable prospectus supplement and/or related free writing prospectus.

No Recourse

There is no recourse under any obligation, covenant or agreement in the applicable indenture or with respect to any security against any of our or our successor’s past, present or future stockholders, employees, officers or directors.

Governing Law

The indenture and the debt securities shall be construed in accordance with and governed by the laws of the State of New York.

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DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of shares of our common stock, shares of preferred stock or our debt securities. We may issue warrants independently or together with other securities, and they may be attached to or separate from the other securities. Each series of warrants will be issued under a separate warrant agreement that we will enter into with a bank or trust company, as warrant agent, as detailed in an accompanying prospectus supplement. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation, or agency or trust relationship, with you.

The prospectus supplement relating to a particular issue of warrants will describe the terms of those warrants, including, when applicable:

After warrants expire they will become void. The prospectus supplement may provide for the adjustment of the exercise price of the warrants.

Warrants may be exercised at the appropriate office of the warrant agent or any other office indicated in an accompanying prospectus supplement. Before the exercise of warrants, holders will not have any of the rights of holders of the securities purchasable upon exercise and will not be entitled to payments made to holders of those securities.

The description in an accompanying prospectus supplement of any warrants we offer will not necessarily be complete and will be qualified in its entirety by reference to the applicable warrant agreement, which will be filed with the SEC if we offer warrants. For more information on how you can obtain copies of any warrant agreement if we offer warrants, see “Where You Can Find More Information.” We urge you to read the applicable warrant agreement and any accompanying prospectus supplement in their entirety.

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DESCRIPTION OF SUBSCRIPTION RIGHTS

We may issue subscription rights to purchase shares of our common stock, shares of our preferred stock or our debt securities. We may issue subscription rights independently or together with any other offered security, which may or may not be transferable by the stockholder. In connection with any offering of subscription rights, we may enter into a standby arrangement with one or more underwriters or other purchasers pursuant to which the underwriters or other purchasers may be required to purchase any securities remaining unsubscribed for after such offering.

The prospectus supplement relating to any subscription rights we may offer will contain the specific terms of the subscription rights. These terms may include the following:

The description in an accompanying prospectus supplement of any subscription rights we offer will not necessarily be complete and will be qualified in its entirety by reference to the applicable subscription rights certificate or subscription rights agreement, which will be filed with the SEC if we offer subscription rights. For more information on how you can obtain copies of any subscription rights certificate or subscription rights agreement if we offer subscription rights, see “Where You Can Find More Information.” We urge you to read the applicable subscription rights certificate, the applicable subscription rights agreement and any accompanying prospectus supplement in their entirety.

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DESCRIPTION OF UNITS

We may issue units comprised of shares of common stock, shares of preferred stock, debt securities and warrants in any combination. We may issue units in such amounts and in as many distinct series as we wish. This section outlines certain provisions of the units that we may issue. If we issue units, they will be issued under one or more unit agreements to be entered into between us and a bank or other financial institution, as unit agent. The information described in this section may not be complete in all respects and is qualified entirely by reference to the unit agreement with respect to the units of any particular series. The specific terms of any series of units offered will be described in a prospectus supplement and/or any related free writing prospectus. If so described in a prospectus supplement and/or any related free writing prospectus, the specific terms of any series of units may differ from the general description of terms presented below. We urge you to read any prospectus supplement and/or any related free writing prospectus related to any series of units we may offer, as well as the complete unit agreement and unit certificate that contain the terms of the units. If we issue units, forms of unit agreements and unit certificates relating to such units will be incorporated by reference as exhibits to the registration statement of which this prospectus forms a part.

Each unit that we may issue will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date. The applicable prospectus supplement and/or any related free writing prospectus may describe:

The provisions described in this section, as well as those described under “Description of Capital Stock,” “Description of Debt Securities” and “Description of Warrants” will apply to the securities included in each unit, to the extent relevant and as may be updated in any prospectus supplements and/or any related free writing prospectus.

Issuance in Series

We may issue units in such amounts and in any number of distinct series. This section summarizes terms of the units that apply generally to all series. Most of the financial and other specific terms of a particular series of units will be described in the applicable prospectus supplement and/or any related free writing prospectus.

Unit Agreements

We will issue the units under one or more unit agreements to be entered into between us and a bank or other financial institution, as unit agent. We may add, replace or terminate unit agents from time to time. We will identify the unit agreement under which each series of units will be issued and the unit agent under that agreement in the applicable prospectus supplement and/or any related free writing prospectus.

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The following provisions will generally apply to all unit agreements unless otherwise stated in the applicable prospectus supplement and/or any related free writing prospectus:

Modification without Consent

We and the applicable unit agent may amend any unit or unit agreement without the consent of any holder:

We do not need any approval to make changes that affect only units to be issued after the changes take effect. We may also make changes that do not adversely affect a particular unit in any material respect, even if they adversely affect other units in a material respect. In those cases, we do not need to obtain the approval of the holder of the unaffected unit; we need only obtain any required approvals from the holders of the affected units.

Modification with Consent

We may not amend any particular unit or a unit agreement with respect to any particular unit unless we obtain the consent of the holder of that unit, if the amendment would:

Any other change to a particular unit agreement and the units issued under that agreement would require the following approval:

These provisions regarding changes with majority approval also apply to changes affecting any securities issued under a unit agreement, as the governing document.

In each case, the required approval must be given by written consent.

Unit Agreements Will Not Be Qualified under Trust Indenture Act

No unit agreement will be qualified as an indenture, and no unit agent will be required to qualify as a trustee, under the Trust Indenture Act. Therefore, holders of units issued under unit agreements will not have the protections of the Trust Indenture Act with respect to their units.

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Mergers and Similar Transactions Permitted; No Restrictive Covenants or Events of Default

The unit agreements will not restrict our ability to merge or consolidate with, or sell our assets to, another corporation or other entity or to engage in any other transactions. If at any time we merge or consolidate with, or sell our assets substantially as an entirety to, another corporation or other entity, the successor entity will succeed to and assume our obligations under the unit agreements. We will then be relieved of any further obligation under these agreements.

The unit agreements will not include any restrictions on our ability to put liens on our assets, nor will they restrict our ability to sell our assets. The unit agreements also will not provide for any events of default or remedies upon the occurrence of any events of default.

Governing Law

The unit agreements and the units will be governed by Delaware law.

Form, Exchange and Transfer

Unless the accompanying prospectus supplement and/or any related free writing prospectus states otherwise, we will issue each unit in global form (i.e., book-entry) only. Units in book-entry form will be represented by a global security registered in the name of a depositary, which will be the holder of all the units represented by the global security. Those who own beneficial interests in a unit will do so through participants in the depositary’s system, and the rights of these indirect owners will be governed solely by the applicable procedures of the depositary and its participants. We will describe book-entry securities, and other terms regarding the issuance and registration of the units in the applicable prospectus supplement and/or any related free writing prospectus.

Unless the accompanying prospectus supplement and/or any related free writing prospectus states otherwise, each unit and all securities comprising the unit will be issued in the same form.

If we issue any units in registered, non-global form, the following will apply to them.

The units will be issued in the denominations stated in the applicable prospectus supplement and/or any related free writing prospectus. Holders may exchange their units for units of smaller denominations or combined into fewer units of larger denominations, as long as the total amount is not changed.

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Only the depositary will be entitled to transfer or exchange a unit in global form, since it will be the sole holder of the unit.

Payments and Notices

In making payments and giving notices with respect to our units, we will follow the procedures as described in the applicable prospectus supplement and/or any related free writing prospectus.

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PLAN OF DISTRIBUTION

We may sell the securities being offered hereby in one or more of the following ways from time to time:

In addition, we may enter into derivative or hedging transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. In connection with such a transaction, the third parties may sell securities covered by and pursuant to this prospectus and any accompanying prospectus supplement. If so, the third party may use securities borrowed from us or the selling stockholders or others to settle such sales and may use securities received from us to close out any related short positions. We may also loan or pledge securities covered by this prospectus and any accompanying prospectus supplement to third parties, who may sell the loaned securities or, in an event of default in the case of a pledge, sell the pledged securities pursuant to this prospectus and any accompanying prospectus supplement.

We will identify the specific plan of distribution, including any underwriters, dealers, agents or direct purchasers and their compensation in a prospectus supplement.

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LEGAL MATTERS

Unless otherwise indicated in any accompanying prospectus supplement, Skadden, Arps, Slate, Meagher & Flom LLP will provide opinions regarding the authorization and validity of the securities. Skadden, Arps, Slate, Meagher & Flom LLP may also provide opinions regarding certain other matters. Any underwriters will be advised about legal matters by their own counsel, which will be named in an accompanying prospectus supplement.

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EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2022, as set forth in their report, which is incorporated by reference in this prospectus and elsewhere in the registration statement. Our consolidated financial statements are incorporated by reference in reliance on Ernst & Young LLP’s reports, given on their authority as experts in accounting and auditing.

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634,500 Shares of Common Stock

Warrants to Purchase 634,500 Shares of Common Stock

PROSPECTUS SUPPLEMENT

June 17, 2024