PLUS THERAPEUTICS, INC.

On May 2, 2025, at a special meeting of stockholders (the “Special Meeting”), our stockholders voted in favor of authorizing our Board to effect a reverse stock split of all of our outstanding shares of Common Stock at a specific ratio within a range of one-for-twenty five (1-for-25) to a maximum of one-for-two hundred fifty (1-for-250), (the “May 2025 Approval”).

Our Board has unanimously approved and declared advisable and is recommending that our stockholders approve and adopt a proposed amendment to our Certificate of Incorporation to combine the outstanding shares of our Common Stock into a lesser number of outstanding shares, in substantially the form attached hereto as Appendix A, to effect an additional reverse stock split of all of our outstanding shares of Common Stock at a specific ratio within a range of one-for-two (1-for-2) to a maximum of a one-for-two hundred fifty (1-for-250), (the “Reverse Stock Split”), with the final decision of whether to proceed with the Reverse Stock Split, the effective time of the Reverse Stock Split, and the exact ratio of the Reverse Stock Split to be determined by our Board, in its sole discretion and without further action by the Company’s stockholders; provided, however, that our Board will not select a reverse split ratio that will result in us having fewer than 500,000 publicly held shares under the Nasdaq continued listing standards. The following table contains approximate information relating to our Common Stock immediately following the Reverse Stock Split under certain possible exchange ratios, based on share information as of June 18, 2025 (all share numbers are rounded down to the nearest whole share):

By approving the Reverse Stock Split, stockholders will approve the Reverse Stock Split at a specific ratio within the range described above as determined by the Board, as it determines to be in the best interest of the Company’s stockholders. The Board believes that stockholder approval of the range of reverse stock split ratios (as opposed to approval of a single reverse stock split ratio) provides the Board with maximum flexibility to achieve the purpose of the Reverse Stock Split, as discussed below, and therefore is in the best interests of the Company and its stockholders.

If our stockholders approve the Reverse Stock Split, and our Board decides to implement it, the Reverse Stock Split will become effective as of a date and time to be determined by the Board that will be specified in the certificate of amendment (the “Effective Time”). If the Board does not decide to implement the Reverse Stock Split within twelve (12) months from the date of the Annual Meeting, the authority granted in this proposal to implement the Reverse Stock Split will terminate.

The Reverse Stock Split will be realized simultaneously for all outstanding Common Stock. The Reverse Stock Split, if implemented, will affect all holders of Common Stock uniformly and each stockholder will hold the same percentage of Common Stock outstanding immediately following the Reverse Stock Split as that stockholder held immediately prior to the Reverse Stock Split, except for immaterial adjustments that may result from the treatment of fractional shares as further described below. The Reverse Stock Split, if implemented, will not change the par value of our Common Stock or the number of authorized shares of Common Stock. The Reverse Stock Split will also affect outstanding stock options and other stock-based awards, as described in “Principal Effects of Reverse Stock Split on Our Equity Plan and Equity Awards Thereunder” below.

In fixing the ratio, the Board may consider, among other things, factors such as the initial and continued listing requirements of Nasdaq Capital Market, the number of shares of our Common Stock outstanding, potential financing opportunities, and prevailing general market and economic conditions.

The Reverse Stock Split, if approved by our stockholders, would become effective upon the filing of the amendment to our Certificate of Incorporation with the Secretary of State of Delaware, or at the later time set forth in the amendment. The timing of the amendment will be determined by the Board based on its evaluation as to when such action will be the most advantageous to our Company and our stockholders. In addition, the Board reserves the right, notwithstanding stockholder approval and without further action by the stockholders, to abandon such an amendment and the Reverse Stock Split if, at any time prior to the effectiveness of the filing of the amendment with the Secretary of State of Delaware, the Board, in its sole discretion, determines that it is no longer in our best interest and the best interests of our stockholders to proceed.

The proposed form of amendment to our Certificate of Incorporation to affect the Reverse Stock Split is attached as Appendix A to this Proxy Statement. Any amendment to our Certificate of Incorporation to affect the Reverse Stock Split will include the Reverse Stock Split ratio fixed by the Board, within the range approved by our stockholders.

Reasons for the Reverse Stock Split

To increase the per share price of our Common Stock

Our Common Stock is currently listed for trading on the Nasdaq Capital Market. As discussed above, the main objective for effecting the Reverse Stock Split, should our Board choose to effect one, would be to increase the per share price of the Common Stock to maintain compliance with the listing standards and policies of the Nasdaq Capital Market. There can be no assurance, however, that the market price of our Common Stock will remain at a level that will be sufficient to meet any requirements and policies of the Nasdaq Capital Market or that our Common Stock will remain listed on the Nasdaq Capital Market. In the event that we are not successful in maintaining the listing of our Common Stock on the Nasdaq Capital Market, we intend to seek a listing on another national securities exchange, which will also require that the per share trading price of our Common Stock be higher than our current per share trading price. In addition, our Board believes that, should the appropriate circumstances arise, effecting the Reverse Stock Split, could, among other things, help us to appeal to a broader range of investors, generate greater investor interest in the Company, and improve the perception of our Common Stock as an investment security.

As previously reported on our Current Report on Form 8-K, filed with the SEC on May 19, 2025, on May 16, 2025, we received notice from The Nasdaq Stock Market LLC (“Nasdaq”) that, because the closing bid price for the Company’s common stock has fallen below $1.00 per share for 30 consecutive business days, the Company no longer complies with the minimum bid price requirement pursuant to Nasdaq Listing Rule 5550(a)(2) (the “Minimum Bid Requirement”).

Nasdaq’s notice has no immediate effect on the listing or trading of the Company’s Common Stock. Pursuant to Nasdaq Listing Rule 5810(c)(3)(A), the Company is provided an initial compliance period of 180 calendar days, or until November 12, 2025, to regain compliance with the Minimum Bid Requirement. To regain compliance, the closing bid price of the Company’s common stock must meet or exceed $1.00 per share for a minimum of 10 consecutive business days prior to November 12, 2025.

If the Company does not achieve compliance with the Minimum Bid Requirement by November 12, 2025, the Company may be eligible for an additional 180 calendar days to regain compliance. To qualify, the Company would be required to meet the continued listing requirement for market value of publicly held shares and all other Nasdaq initial listing standards, with the exception of the Minimum Bid Requirement, and provide written notice of its intention to cure the minimum bid price deficiency during the second compliance period by effecting a reverse stock split if necessary. If the Nasdaq staff determines that the Company will not be able to cure the deficiency, or if the Company is otherwise not eligible for such additional compliance period, Nasdaq will provide notice that the Company’s common stock will be subject to delisting. In the event the Company receives notice that its common stock is being delisted, Nasdaq rules permit the Company to appeal any delisting determination by the Nasdaq staff. There can be no assurance that the Company will be able to regain compliance with the Minimum Bid Requirement or maintain compliance with the other listing requirements.

The Company intends to monitor the closing bid price of its common stock and may, if appropriate, consider implementing available options to regain compliance with the Minimum Bid Requirement.

To potentially improve the liquidity of our Common Stock

The Reverse Stock Split could allow a broader range of institutions to invest in the Common Stock (namely, funds that are prohibited from buying stocks whose price is below certain thresholds), potentially increasing trading volume and liquidity of the Common Stock and potentially decreasing the volatility of the Common Stock if institutions become long-term holders of the Common Stock. The Reverse Stock Split could help increase analyst and broker interest in the Common Stock as their policies can discourage them from following or recommending companies with low stock prices. Because of the trading volatility often associated with low-priced stocks, many brokerage houses and institutional investors have internal policies and practices that either prohibit them from investing in low-priced stocks or tend to discourage individual brokers from recommending low-priced stocks to their customers. Some of those policies and practices may make the processing of trades in low-priced stocks economically unattractive to brokers. Additionally, because brokers’ commissions on low-priced stocks generally represent a higher percentage of the stock price than commissions on higher-priced stocks, a low average price per share of Common Stock can result in individual stockholders paying transaction costs representing a higher percentage of their total share value than would be the case if the share price were higher. Some investors, however, may view the Reverse Stock Split negatively because it reduces the number of shares of Common Stock available in the public market.

The Board believes that retaining our listing on the Nasdaq Capital Market is in the best interests of the Company and our stockholders and is crucial to stockholder value and liquidity and our long-term business prospects.

Determination of Reverse Stock Split Ratio

Our Board believes that stockholder adoption of several fixed reverse stock split ratios, as opposed to adoption of a single reverse stock split ratio, provides maximum flexibility to achieve the purposes of the Reverse Stock Split and, therefore, is in the best interests of the Company and its stockholders. In determining which of the approved fixed ratios to implement following the receipt of stockholder approval, the Board (or any authorized committee of the Board) may consider, among other things, factors such as:

The Board reserves the right to elect to abandon the Reverse Stock Split (including all of the fixed reverse stock split ratios), notwithstanding stockholder approval thereof, if our Board determines, in its sole discretion, that the Reverse Stock Split is no longer in the best interests of the Company and its stockholders. In making such determination, our Board will take into account certain factors including the expected trading prices for our Common Stock, actual or forecasted results of operations and the likely effect of such results on the market price of our Common Stock, as well as the factors described in the above paragraph.

Procedure for Effecting Reverse Stock Split

If the Reverse Stock Split is approved by the Company’s stockholders, and if at such time the Board still believes that a reverse stock split is in the best interests of the Company and its stockholders, the Board will determine the ratio of the Reverse Stock Split to be implemented. The Reverse Stock Split will become effective as of the Effective Time. The Board will determine the exact timing and effectiveness of the filing of the certificate of amendment based on its evaluation as to when the filing would be the most advantageous to the Company and its stockholders. If the Board does not decide to implement the Reverse Stock Split within twelve (12) months from the date of the Annual Meeting, the authority granted in this proposal to implement the Reverse Stock Split will terminate.

Except as described below in the sections titled “Fractional Shares” and “Principal Effects of Reverse Stock Split on Our Equity Plan and Equity Awards Thereunder,” at the Effective Time, each whole number of issued and outstanding pre-Reverse Stock Split shares that the Board has determined will be combined into one post-Reverse Stock Split share (based on the Board’s final selection of the fixed ratio to be applied) will, automatically and without any further action on the part of our stockholders, be combined into and become one share of Common Stock, and each certificate that, immediately prior to the Effective Time represented pre-Reverse Stock Split shares, will be deemed for all corporate purposes to evidence ownership of post-Reverse Stock Split shares.

Fractional Shares

No fractional shares will be issued in connection with the Reverse Stock Split. Stockholders of record at the Effective Time of the Reverse Stock Split who otherwise would be entitled to receive fractional shares because they hold a number of pre-Reverse Stock Split shares not evenly divisible by the number of pre-Reverse Stock Split shares for which each post-Reverse Stock Split share is to be exchanged, will, in lieu of a fractional share, be entitled, upon surrender to the exchange agent of certificate(s) representing such pre-Reverse Stock Split shares (except as described below under “—Book-Entry Shares”), to a cash payment, without interest, in lieu thereof, as set forth in the certificate of amendment.

Stockholders should be aware that, under the escheat laws of the various jurisdictions where stockholders reside, sums due for fractional interests that are not timely claimed after the Effective Time may be required to be paid to the designated agent for each such jurisdiction. Thereafter, stockholders otherwise entitled to receive such funds may have to seek to obtain them directly from the state to which they were paid. Stockholders will not be entitled to receive interest for the period of time between the Effective Time and the date payment is received.

Book-Entry Shares

If the Reverse Stock Split is effected, stockholders who hold uncertificated shares (i.e., shares held in book-entry form and not represented by a physical stock certificate), either as direct or beneficial owners, will have their holdings electronically adjusted automatically by our transfer agent (and, for beneficial owners, by their brokers or banks that hold in “street name” for their benefit, as the case may be) to give effect to the Reverse Stock Split. Stockholders who hold uncertificated shares as direct owners will be sent a statement of holding from our transfer agent that indicates the number of post-Reverse Stock Split shares of our Common Stock owned in book-entry form.

Certificated Shares

As soon as practicable after the Effective Time of the Reverse Stock Split, stockholders will be notified that the Reverse Stock Split has been effected. We expect that our transfer agent will act as exchange agent for purposes of implementing the exchange of stock certificates. Holders of pre-Reverse Stock Split shares will be asked to surrender to the exchange agent certificates representing pre-Reverse Stock Split shares in exchange for certificates representing post-Reverse Stock Split shares in accordance with the procedures to be set forth in a letter of transmittal to be sent by us or our exchange agent. No new certificates will be issued to a stockholder until such stockholder has surrendered such stockholder’s outstanding certificate(s) together with the properly completed and executed letter of transmittal to the exchange agent. Any pre-Reverse Stock Split shares submitted for transfer, whether pursuant to a sale or other disposition, or otherwise, will automatically be exchanged for post-Reverse Stock Split shares. STOCKHOLDERS SHOULD NOT DESTROY ANY STOCK CERTIFICATE(S) AND SHOULD NOT SUBMIT ANY CERTIFICATE(S) UNTIL REQUESTED TO DO SO.

Potential Effects of the Proposed Amendment

If our stockholders approve the Reverse Stock Split and the Board effects it, the number of shares of Common Stock issued and outstanding will be reduced, depending upon the ratio determined by the Board. The Reverse Stock Split will affect all holders of our Common Stock uniformly and will not affect any stockholder’s percentage ownership interest in the Company, except that as described above in the section titled “Fractional Shares,” record holders of Common Stock otherwise entitled to a fractional share as a result of the Reverse Stock Split because they hold a number of shares not evenly divisible by the Reverse Stock Split ratio will automatically be entitled to receive an additional fraction of a share of Common Stock to round up to the next whole share. For those stockholders who hold shares with a brokerage firm, the Company intends to round up fractional shares at the participant level. The Reverse Stock Split will not affect any stockholder’s proportionate voting power (subject to the treatment of fractional shares).

The Reverse Stock Split will not change the terms of the Common Stock. Additionally, the Reverse Stock Split will have no effect on the number of shares of Common Stock that we are authorized to issue. At the time of this proposal, we have 2,000,000,000 authorized shares of Common Stock. After the Reverse Stock Split, the shares of Common Stock will have the same voting rights and rights to dividends and distributions and will be identical in all other respects to the Common Stock now authorized. Our outstanding shares of Common Stock will remain fully paid and non-assessable.

After the effective time of the Reverse Stock Split, we will continue to be subject to the periodic reporting and other requirements of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

Principal Effects of Reverse Stock Split on Our Equity Plan and Equity Awards Thereunder

Pursuant to the terms of our 2020 Stock Incentive Plan, as amended and restated (the “2020 Plan”) and the agreements governing equity awards thereunder, the Board or a committee thereof, as applicable, will adjust the number of shares of Common Stock available for future grant, the number of shares of Common Stock underlying outstanding awards, the exercise price per share of outstanding stock options, and other terms of outstanding awards issued pursuant to the 2020 Plan to equitably reflect the effects of the Reverse Stock Split. With respect to any such outstanding equity awards, the contemplated equitable adjustments will result in approximately the same aggregate exercise price being required to be paid under such stock options, and approximately the same value of shares of Common Stock being delivered upon exercise, vesting or settlement of such awards immediately following the Reverse Stock Split as was the case immediately preceding the Reverse Stock Split. Any fractional shares that would otherwise result from the Reverse Stock Split adjustments described above with respect to outstanding equity awards will be eliminated through rounding or as otherwise determined by the Board or a committee thereof in accordance with the terms of the 2020 Plan and award agreements thereunder.

Registered “Book-Entry” Holders of Common Stock

Our registered holders of Common Stock hold some or all of their shares electronically in book-entry form with the transfer agent. These stockholders do not have stock certificates evidencing their ownership of the Common Stock. They are, however, provided with statements reflecting the number of shares registered in their accounts.

Stockholders who hold shares electronically in book-entry form with the transfer agent will not need to take action to receive evidence of their shares of post-Reverse Stock Split Common Stock.

Effect of the Reverse Stock Split on Outstanding Stock Options and Warrants

Based upon the Reverse Stock Split ratio, proportionate adjustments are generally required to be made to the per share exercise price and the number of shares issuable upon the exercise of all outstanding options and warrants. This would result in approximately the same aggregate price being required to be paid under such options or warrants upon exercise, and approximately the same value of shares of Common Stock being delivered upon such exercise immediately following the Reverse Stock Split as was the case immediately preceding the Reverse Stock Split. The number of shares reserved for issuance pursuant to these securities will be reduced proportionately based upon the Reverse Stock Split ratio.

Accounting Matters

The proposed amendment to our Certificate of Incorporation will not affect the par value of our Common Stock. As a result, at the effective time of the Reverse Stock Split, the stated capital on our balance sheet attributable to the Common Stock will be reduced in the same proportion as the Reverse Stock Split ratio, and the additional paid-in capital account will be credited with the amount by which the stated capital is reduced. The per share net income or loss will be restated for prior periods to conform to the post-Reverse Stock Split presentation.

No Dissenters’ or Appraisal Rights

Under the Delaware General Corporation Law, our stockholders are not entitled to any dissenters’ or appraisal rights with respect to the Reverse Stock Split, and we will not independently provide stockholders with any such right.

Effect on Par Value

The certificate of amendment will not affect the par value of our Common Stock, which will remain at $0.001 per share.

Dividends

We have never declared or paid cash dividends on our capital stock. We currently intend to retain all of our future earnings, if any, to finance the operation, development and growth of our business. While the timing, declaration and payment of any future dividends to holders of our Common Stock fall within the discretion of our Board and will depend on our operating results, earnings, financial condition, the capital requirements of our business and other factors, our Board expects that the amount of future dividends, if any, would be adjusted accordingly to reflect the Reverse Stock Split.

No Going Private Transaction

Notwithstanding the decrease in the number of outstanding shares following the Reverse Stock Split, our Board does not intend for this transaction to be the first step in a “going private transaction” within the meaning of Rule 13e-3 under the Exchange Act.

Certain U.S. Federal Income Tax Consequences of the Reverse Stock Split

The following is a summary of important tax considerations of the Reverse Stock Split. It addresses only stockholders who hold our Common Stock as capital assets. It does not purport to be complete and does not address stockholders subject to special rules, such as financial institutions, tax-exempt organizations, insurance companies, dealers in securities, foreign stockholders, stockholders who hold their pre-Reverse Stock Split shares as part of a straddle, hedge or conversion transaction, and stockholders who acquired their pre-Reverse Stock Split shares pursuant to the exercise of employee stock options or otherwise as compensation. This summary is based upon current law, which may change, possibly even retroactively. It does not address tax considerations under state, local, foreign and other laws. The tax treatment of a stockholder may vary depending upon the particular facts and circumstances of such stockholder. Each stockholder is urged to consult with such stockholder’s own tax advisor with respect to the tax consequences of the Reverse Stock Split.

The Reverse Stock Split is intended to constitute a reorganization within the meaning of Section 368 of the Internal Revenue Code of 1986, as amended. Assuming the Reverse Stock Split qualifies as a reorganization, a stockholder generally will not recognize gain or loss on the Reverse Stock Split, except to the extent of cash, if any, received in lieu of a fractional share interest. The aggregate tax basis of the post-Reverse Stock Split shares received will be equal to the aggregate tax basis of the pre-Reverse Stock Split shares exchanged therefor (excluding any portion of the holder’s basis allocated to fractional shares), and the holding period of the post- Reverse Stock Split shares received will include the holding period of the pre-Reverse Stock Split shares exchanged.

A holder of the pre-Reverse Stock Split shares who receives cash will generally be treated as having exchanged a fractional share interest for cash in a redemption by us. The amount of any gain or loss will be equal to the difference between the portion of the tax basis of the pre-Reverse Stock Split shares allocated to the fractional share interest and the cash received and generally should be capital gain or loss and generally would be a long-term gain or loss to the extent that the holder’s holding period exceeds twelve (12) months.

The foregoing views are not binding on the Internal Revenue Service or the courts. Accordingly, each stockholder should consult with their own tax advisor with respect to all of the potential tax consequences to them of the Reverse Stock Split.

Reservation of Right to Abandon Reverse Stock Split

We reserve the right to not file the certificate of amendment and to abandon any Reverse Stock Split (including all of the fixed reverse stock split ratios) without further action by our stockholders at any time before the effectiveness of the filing with the Secretary of State of the State of Delaware of the certificate of amendment, even if the authority to effect these amendments is approved by our stockholders at the Annual Meeting. By voting in favor of the Reverse Stock Split (including each of the fixed reverse stock split ratios), you are expressly also authorizing the Board to delay, not proceed with, and abandon, the Reverse Stock Split (including all of the fixed reverse stock split ratios) and the certificate of amendment if it should so decide, in its sole discretion, that such actions are in the best interests of our stockholders.

May 2025 Approval

Whether or not the Reverse Stock Split Proposal is approved, our Board may effect a reverse stock split pursuant to the May 2025 Approval.

Interests of Officers and Directors in this Proposal

Our officers and directors do not have any substantial interest, direct or indirect, in this proposal.

The affirmative vote of a majority of the outstanding shares of Common Stock entitled to vote on this proposal is required to approve the Reverse Stock Split Proposal. The affirmative vote of a majority of all votes cast by the holders of shares of Common Stock entitled to vote will be required for approval. Abstentions and broker non-votes, if any, will have no effect on the outcome of this proposal.

YOUR BOARD UNANIMOUSLY RECOMMENDS A VOTE “FOR” THE APPROVAL OF THE REVERSE STOCK SPLIT PROPOSAL.