Oaktree Acquisition Corp. III Life Sciences

DEF 14A 1 d57016ddef14a.htm DEF 14A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Oaktree Acquisition Corp. III Life Sciences

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

LETTER TO SHAREHOLDERS OF OAKTREE ACQUISITION CORP. III LIFE SCIENCES

Dear Oaktree Acquisition Corp. III Life Sciences Shareholder:

You are cordially invited to attend an extraordinary general meeting in lieu of annual meeting of Oaktree Acquisition Corp. III Life Sciences, a Cayman Islands exempted company (“OAC” or the “Company”), which will be held on October 16, 2026, at 11:00 a.m., Eastern Time, at the offices of Kirkland & Ellis LLP located at 601 Lexington Avenue, New York, NY 10022, and via a virtual meeting, or at such other time, on such other date and at such other place to which the meeting may be postponed or adjourned (the “Shareholder Meeting”).

The Shareholder Meeting will be conducted via live webcast, but the physical location of the Shareholder Meeting will remain at the location specified above for the purposes of our amended and restated memorandum and articles of association (the “Memorandum and Articles of Association”). If you wish to attend the Shareholder Meeting in person, you must reserve your attendance at least two business days in advance of the Shareholder Meeting by contacting OAC’s Chief Executive Officer at info@oaktreeacquisitioncorp.com by 11:00 a.m., Eastern Time, on October 14, 2026 (two business days prior to the initially scheduled meeting date). You will be able to attend the Shareholder Meeting online, vote and submit your questions during the Shareholder Meeting by visiting https://www.cstproxy.com/oac-iii/2026. In addition to the formal business of the Shareholder Meeting described below, shareholders will have the opportunity to ask questions regarding the Company’s business, affairs and operations, including questions regarding the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, and the audited financial statements contained therein. The attached notice of the Shareholder Meeting and proxy statement describe the business OAC will conduct at the Shareholder Meeting and provide information about OAC that you should consider when you vote your shares. As more fully described in the attached proxy statement, which is dated October 2, 2026, and is first being mailed to shareholders on or about that date, together with the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, the Shareholder Meeting will be held for the purpose of considering and voting on the following proposals:

The purpose of the Extension Amendment Proposal is to allow OAC additional time to complete a Business Combination. The purpose of the Adjournment Proposal is to provide additional time, if necessary, to obtain sufficient votes in support of the Extension Amendment Proposal or to allow public shareholders time to reverse their redemption requests with the Articles Extension.You are not being asked to vote on a Business Combination at this time.

The Memorandum and Articles of Association provide that OAC has until October 25, 2026 to complete its initial Business Combination. OAC’s Board has determined that it is in the best interests of OAC to seek an extension of the Termination Date and have OAC’s shareholders approve the Extension Amendment Proposal to allow for a period of additional time to consummate a Business Combination. Without the Articles Extension, OAC believes that it will not be able to complete a Business Combination on or before the Termination Date. If that were to occur, OAC would be precluded from completing a Business Combination and would be forced to liquidate.

OAC reserves the right at any time to postpone or cancel the Shareholder Meeting (by means of adjourning the Shareholder Meeting indefinitely) and not to submit to its shareholders the Extension Amendment Proposal or implement the Articles Extension. In the event the Shareholder Meeting is postponed, adjourned or canceled, and OAC is unable to complete a Business Combination on or before the Termination Date, OAC will wind up, dissolve and liquidate in accordance with the Memorandum and Articles of Association.

As contemplated by the Memorandum and Articles of Association, the holders of OAC’s Class A Ordinary Shares issued as part of the Units (as defined below) sold in OAC’s initial public offering (the “Public Shares”) may elect to redeem all or a portion of their Public Shares in exchange for their pro rata portion of the funds held in a trust account (the “Trust Account”) established to hold a portion of the proceeds of the initial public offering and the concurrent sale of the private placement warrants, if the Articles Extension is implemented, regardless of how such public shareholders vote in regard to the Extension Amendment Proposal.If the Extension Amendment Proposal is approved by the requisite vote of shareholders, the holders of Public Shares remaining after the redemption will retain their right to redeem their Public Shares in connection with a Business Combination or liquidation, subject to any limitations set forth in the Memorandum and Articles of Association, as amended by the Articles Extension Date or the relevant Additional Articles Extension.

On September 30, 2026, the most recent practicable date prior to the date of the accompanying proxy statement, the redemption price per share was approximately $10.75, based on the aggregate amount on deposit in the Trust Account of approximately $206,314,849 as of September 30, 2026 (including interest not previously released to OAC), divided by the total number of then outstanding Public Shares. The redemption price per share will be calculated based on the aggregate amount on deposit in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to OAC, two business days prior to the initially scheduled date of the Shareholder Meeting. The closing price of the Class A Ordinary Shares on The Nasdaq Stock Market LLC (“Nasdaq”) on October 1, 2026 was $10.78. Accordingly, if the market price of the Class A Ordinary Shares were to remain the same until the date of the Shareholder Meeting, exercising redemption rights would result in a public shareholder receiving approximately $0.03 less per share than if the shares were sold in the open market (based on the per share redemption price as of September 30, 2026). OAC cannot assure shareholders that they will be able to sell their Class A Ordinary Shares in the open market, even if the market price per share is higher than the redemption price stated above, as there may not be sufficient liquidity in its securities when such shareholders wish to sell their shares. OAC believes that such redemption right enables its public shareholders to determine whether to sustain their investments for an additional period if OAC does not complete a Business Combination on or before the Termination Date.

If the Extension Amendment Proposal is not approved, and a Business Combination is not completed on or before the Termination Date, OAC will: (i) cease all operations except for the purpose of winding up; (ii) as promptly as reasonably possible but not more than ten business days thereafter, redeem the Public Shares, at aper-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to OAC (less taxes payable and up to $100,000 of interest to pay winding up and dissolution expenses), divided by the total number of the then-outstanding Public Shares, which redemption will completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidation distributions, if any); and (iii) as promptly as reasonably possible following such redemption, subject to the approval of OAC’s remaining shareholders and the Board, liquidate and dissolve, subject in each case to OAC’s obligations under Cayman Islands law to provide for claims of creditors and other requirements of applicable law. There will be no distribution from the Trust Account with respect to OAC’s Warrants (as defined below), which will expire worthless in the event OAC dissolves and liquidates the Trust Account.

Subject to the foregoing, the approval of the Extension Amendment Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of at least atwo-thirds (2/3) majority of the votes cast by the holders of Class A Ordinary Shares and Class B Ordinary Shares voting as a single class, who are present in person or represented by proxy and entitled to vote thereon, and who vote thereon, at the Shareholder Meeting.

Approval of the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of at least a majority of the votes cast by the holders of the issued Class A Ordinary Shares and Class B Ordinary Shares, voting as a single class, who are present in person or represented by proxy and entitled to vote thereon, and who vote thereon, at the Shareholder Meeting. The Adjournment Proposal will only be put forth for a vote if there are not sufficient votes to approve the Extension Amendment Proposal at the Shareholder Meeting or if the Board has determined it is otherwise necessary.

The Board has fixed the close of business on September 22, 2026 as the date for determining OAC’s shareholders entitled to receive notice of and vote at the Shareholder Meeting and any adjournment thereof. Only holders of record of Ordinary Shares on that date are entitled to have their votes counted at the Shareholder Meeting or any adjournment thereof.

The Board of OAC believes that it is in the best interests of OAC that OAC obtain the Articles Extension. After careful consideration of all relevant factors, the Board has determined that the Extension Amendment Proposal and the Adjournment Proposal are in the best interests of OAC and its shareholders and has declared it advisable and recommends that you vote or give instruction to vote “FOR” the Extension Amendment Proposal and “FOR” the Adjournment Proposal.

Your vote is very important. Whether or not you plan to attend the Shareholder Meeting, please vote as soon as possible by following the instructions in the accompanying proxy statement to make sure that your shares are represented and voted at the Shareholder Meeting. If you hold your shares in “street name” through a bank, broker or other nominee, you will need to follow the instructions provided to you by your bank, broker or other nominee to ensure that your shares are represented and voted at the Shareholder Meeting. The approval of the Extension Amendment Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of at least atwo-thirds (2/3) majority of the votes cast by the holders of the issued Class A Ordinary Shares and Class B Ordinary Shares, voting as a single class, who are present in person or represented by proxy and entitled to vote thereon, and who vote thereon, at the Shareholder Meeting. Approval of the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of at least a majority of the votes cast by the holders of the issued Class A Ordinary Shares and Class B Ordinary Shares, voting as a single class, who are present in person or represented by proxy and entitled to vote thereon, and who vote thereon, at the Shareholder Meeting. Accordingly, if you fail to vote in person or by proxy at the Shareholder Meeting, your shares will not be counted for the purposes of determining whether the Extension Amendment Proposal and the Adjournment Proposal are approved by the requisite majorities.

If you sign, date and return your proxy card without indicating how you wish to vote, your proxy will be voted “FOR” each of the proposals presented at the Shareholder Meeting. If you fail to return your proxy card or fail to instruct your bank, broker or other nominee how to vote, and do not attend the Shareholder Meeting in person, the effect will be that your shares will not be counted for purposes of determining whether a quorum is present at the Shareholder Meeting and will not have any effect on whether the proposals are approved. If you are a shareholder of record and you attend the Shareholder Meeting and wish to vote in person, you may withdraw your proxy and vote in person.

TO EXERCISE YOUR REDEMPTION RIGHTS, YOU MUST DEMAND IN WRITING THAT YOUR CLASS A ORDINARY SHARES ARE REDEEMED FOR A PRO RATA PORTION OF THE FUNDS HELD IN THE TRUST ACCOUNT AND TENDER YOUR SHARES TO OAC’S TRANSFER AGENT AT LEAST TWO BUSINESS DAYS PRIOR TO THE INITIALLY SCHEDULED DATE OF THE SHAREHOLDER MEETING. IN ORDER TO EXERCISE YOUR REDEMPTION RIGHT, YOU NEED TO IDENTIFY YOURSELF AS A BENEFICIAL HOLDER AND PROVIDE YOUR LEGAL NAME, PHONE NUMBER AND

ADDRESS IN YOUR WRITTEN DEMAND. YOU MAY TENDER YOUR SHARES BY EITHER TENDERING OR DELIVERING YOUR SHARES (AND SHARE CERTIFICATES (IF ANY) AND OTHER REDEMPTION FORMS) TO THE TRANSFER AGENT OR BY TENDERING OR DELIVERING YOUR SHARES (AND SHARE CERTIFICATES (IF ANY) AND OTHER REDEMPTION FORMS) ELECTRONICALLY USING THE DEPOSITORY TRUST COMPANY’S DWAC (DEPOSIT WITHDRAWAL AT CUSTODIAN) SYSTEM. IF YOU HOLD THE SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO WITHDRAW THE SHARES FROM YOUR ACCOUNT IN ORDER TO EXERCISE YOUR REDEMPTION RIGHTS.

Enclosed is the proxy statement containing detailed information about the Shareholder Meeting, the Extension Amendment Proposal and the Adjournment Proposal. Whether or not you plan to attend the Shareholder Meeting, OAC urges you to read this material carefully and vote your shares.

The proxy statement mailed to you is also accompanied by OAC’s Annual Report on Form 10-K for the year ended December 31, 2025. Each of such documents is also available on the SEC’s website,* *

at: http://www.sec.gov.

By Order of the Board of Directors of Oaktree Acquisition Corp. III Life Sciences

/s/ Aman Kumar

Chairman of the Board of Directors

OAKTREE ACQUISITION CORP. III LIFE SCIENCES

NOTICE OF AN EXTRAORDINARY GENERAL MEETING IN LIEU OF ANNUAL MEETING OF SHAREHOLDERS

OF OAKTREE ACQUISITION CORP. III LIFE SCIENCES

TO BE HELD ON OCTOBER 16, 2026

To the Shareholders of Oaktree Acquisition Corp. III Life Sciences:

NOTICE IS HEREBY GIVEN that an extraordinary general meeting in lieu of annual meeting of Oaktree Acquisition Corp. III Life Sciences, a Cayman Islands exempted company (“OAC” or the “Company”), will be held on October 16, 2026, at 11:00 a.m., Eastern Time (the “Shareholder Meeting”), at the offices of Kirkland & Ellis LLP located at 601 Lexington Avenue, New York, NY 10022, and via a virtual meeting, or at such other time, on such other date and at such other place to which the meeting may be postponed or adjourned.

The Shareholder Meeting will be conducted via live webcast, but the physical location of the Shareholder Meeting will remain at the location specified above for the purposes of our amended and restated memorandum and articles of association (the “Memorandum and Articles of Association”). If you wish to attend the Shareholder Meeting in person, you must reserve your attendance at least two business days in advance of the Shareholder Meeting by contacting OAC’s Chief Executive Officer at info@oaktreeacquisitioncorp.com by 11:00 a.m., Eastern Time, on October 14, 2026 (two business days prior to the initially scheduled meeting date). You will be able to attend the Shareholder Meeting online, vote and submit your questions during the Shareholder Meeting by visitinghttps://www.cstproxy.com/oac-iii/2026. In addition to the formal business of the Shareholder Meeting described below, shareholders will have the opportunity to ask questions regarding the Company’s business, affairs and operations, including questions regarding the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, and the audited financial statements contained therein.

You are cordially invited to attend the Shareholder Meeting that will be held for the purpose of considering and voting on (i) an extension amendment proposal to amend, by way of special resolution, the Memorandum and Articles of Association to extend the date (the “Termination Date”) by which OAC has to consummate a Business Combination (the “Articles Extension”) from October 25, 2026 (the “Original Termination Date”) to November 25, 2026 (the “Articles Extension Date”) and to allow OAC, without another shareholder vote, to elect to extend the Termination Date to consummate an initial business combination (a “Business Combination”) on a monthly basis for up to six times by an additional one month each time after the Articles Extension Date, by resolution of OAC’s board of directors (the “Board”), if requested by Oaktree Acquisition Holdings III LS, LLC, a Cayman Islands limited liability company (the “Sponsor”), and upon five days’ advance notice prior to the applicable Termination Date (each, an “Additional Articles Extension Date”) for an aggregate extension period of up to seven months after the Original Termination Date, ending no later than May 25, 2027, unless the closing of a Business Combination shall have occurred prior thereto (the “Extension Amendment Proposal”), and (ii) an adjournment proposal to adjourn, by way of ordinary resolution, the Shareholder Meeting to a later date or dates or indefinitely, if necessary, (a) to permit further solicitation and vote of proxies if, based upon the tabulated vote at the time of the Shareholder Meeting, there are insufficient Class A ordinary shares, par value of US$0.0001 per share, of the Company (the “Class*** A Ordinary Shares*”) and Class B ordinary shares, par value of US$0.0001 per share, of the Company (the “Class*** B Ordinary Shares*” and together with Class A Ordinary Shares, the “Ordinary Shares”) represented (either in person or by proxy) at the Shareholder Meeting to approve the Extension Amendment Proposal or (b) where the Board has determined it is otherwise necessary (the “Adjournment Proposal”), each as more fully described below in the accompanying proxy statement, which is dated October 2, 2026, and is first being mailed to shareholders on or about that date. The full text of the proposals to be voted upon at the Shareholder Meeting is as follows:

1.Proposal No. 1 - The Extension Amendment Proposal -** RESOLVED**, as a special resolution that:

“In the event that the Company does not consummate a Business Combination upon the date which is the later of (i) November 25, 2026 (or such later date up to, and including, May 25, 2027, if applicable under the provisions of this Article 164) and (ii) such later date as may be approved by the Members in accordance with the Articles (in any case, such date being referred to as the “Termination Date”), or such earlier date as the board of Directors may approve, the Company shall (i) cease all operations except for the purpose of winding up; (ii) as promptly as reasonably possible but not more than ten business days thereafter, redeem the Public Shares, at aper-Share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Fund, including interest earned on the funds held in the Trust Fund and not released for Permitted Withdrawals (less up to $100,000 to pay winding up and dissolution expenses), divided by the number of Public Shares then in issue, which redemption will completely extinguish public Members’ rights as Members (including the right to receive further liquidation distributions, if any); and (iii) as promptly as reasonably possible following such redemption, subject to the approval of OAC’s remaining Members and the Directors, liquidate and dissolve, subject in the case ofsub-articles (ii) and (iii), to its obligations under Cayman Islands law to provide for claims of creditors and in all cases subject to the other requirements of applicable law. In the event that the Company is wound up for any reason prior to the consummation of a Business Combination, the Company shall also be required to follow the procedures outlined insub-articles (ii) and (iii) of this Article 164(a).

Notwithstanding the foregoing or any other provisions of the Articles, in the event that the Company has not consummated a Business Combination by November 25, 2026, the Company may, without another shareholder vote, elect to extend the date to consummate a Business Combination on a monthly basis for up to six times by an additional one month each time after November 25, 2026, by resolution of the Directors, if requested by the Sponsor in writing, and upon five days’ advance notice prior to the applicable Termination Date, until May 25, 2027.”

shares redeemed in connection with the initial Business Combination or to redeem 100% of the Public Shares if the Company does not complete its initial Business Combination prior to November 25, 2026 (or up to May 25, 2027, if applicable under the provisions of Article 164(a)), or such earlier date as the board of Directors may approve, or with respect to any other provision relating to the rights of holders of Class A Shares, each holder of Public Shares shall be provided with the opportunity to redeem their Public Shares upon the implementation of any such amendment at a per-Share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Fund, including interest earned on the Trust Fund and not released for Permitted Withdrawals divided by the number of Public Shares then in issue.

Each of the Extension Amendment Proposal and the Adjournment Proposal is more fully described in the accompanying proxy statement. Please take the time to read carefully each of the proposals in the accompanying proxy statement before you vote. The accompanying proxy statement is being mailed to shareholders together with OAC’s Annual Report on Form 10-K for the year ended December 31, 2025.

OAC reserves the right at any time to postpone or cancel the Shareholder Meeting (by means of adjourning the Shareholder Meeting indefinitely) and not to submit to its shareholders the Extension Amendment Proposal or implement the Articles Extension. In the event the Shareholder Meeting is postponed, adjourned or canceled, and OAC is unable to complete a Business Combination on or before the Termination Date, OAC will wind up, dissolve and liquidate in accordance with the Memorandum and Articles of Association.

The purpose of the Extension Amendment Proposal is to allow OAC additional time to complete a Business Combination. The purpose of the Adjournment Proposal is to provide additional time, if necessary, to obtain sufficient votes in support of the Extension Amendment Proposal or to allow public shareholders time to reverse their redemption requests with the Articles Extension.You are not being asked to vote on a Business Combination at this time.

The Memorandum and Articles of Association provide that OAC has until October 25, 2026 to complete its initial Business Combination. The Board has determined that it is in the best interests of OAC to seek an extension of the Termination Date and have OAC’s shareholders approve the Extension Amendment Proposal to allow for a period of additional time to consummate a Business Combination. Without the Articles Extension, OAC believes that OAC will not be able to complete a Business Combination on or before the Termination Date. If that were to occur, OAC would be precluded from completing a Business Combination and would be forced to liquidate.

The Board of OAC believes that it is in the best interests of OAC that OAC obtain the Articles Extension. After careful consideration of all relevant factors, the Board has determined that the Extension Amendment Proposal and the Adjournment Proposal are in the best interests of OAC and its shareholders and has declared it advisable and recommends that you vote or give instruction to vote “FOR” the Extension Amendment Proposal and “FOR” the Adjournment Proposal.

As contemplated by the Memorandum and Articles of Association, the holders of OAC’s Class A Ordinary Shares issued as part of the Units (as defined below) sold in OAC’s initial public offering (the “Public Shares”) may elect to redeem all or a portion of their Public Shares in exchange for their pro rata portion of the funds held in the Trust Account established to hold a portion of the proceeds of the initial public offering and the concurrent sale of the private placement warrants (the “Private Placement Warrants”), if the Articles Extension is implemented, regardless of how such public shareholders vote in regard to the Extension Amendment Proposal.If the Extension Amendment Proposal is approved by the requisite vote of shareholders, the holders of Public Shares remaining after the redemption will retain their right to redeem their Public Shares in connection with a Business Combination or liquidation, subject to any limitations set forth in the Memorandum and Articles of Association, as amended.

On September 30, 2026, the most recent practicable date prior to the date of this proxy statement, the redemption price per share was approximately $10.75, based on the aggregate amount on deposit in the Trust Account of approximately $206,314,849 as of September 30, 2026 (including interest not previously released to OAC), divided by the total number of then outstanding Public Shares. The redemption price per share will be calculated based on the aggregate amount on deposit in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to OAC, two business days prior to the initially scheduled date of the Shareholder Meeting. The closing price of the Class A Ordinary Shares on The Nasdaq Stock Market LLC (“Nasdaq”) on October 1, 2026 was $10.78. Accordingly, if the market price of the Class A Ordinary Shares were to remain the same until the date of the Shareholder Meeting, exercising redemption rights would result in a public shareholder receiving approximately $0.03 less per share than if the shares were sold in the open market (based on the per share redemption price as of September 30, 2026). OAC cannot assure shareholders that they will be able to sell their Class A Ordinary Shares in the open market, even if the market price per share is higher than the redemption price stated above, as there may not be sufficient liquidity in its securities when such shareholders wish to sell their shares. OAC believes that such redemption right enables its public shareholders to determine whether to sustain their investments for an additional period if OAC does not complete a Business Combination on or before the Termination Date.

Approval of the Extension Amendment Proposal is a condition to the implementation of the Articles Extension.

OAC cannot predict the amount that will remain in the Trust Account following the redemption if the Extension Amendment Proposal is approved, and the amount remaining in the Trust Account may be only a small fraction of the approximately $206,314,849 that was in the Trust Account as of September 30, 2026 (including interest not previously released to OAC).

If the Extension Amendment Proposal is not approved, and a Business Combination is not completed on or before the Termination Date, OAC will: (i) cease all operations except for the purpose of winding up; (ii) as promptly as reasonably possible but not more than ten business days thereafter, redeem the Public Shares, at aper-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to OAC (less taxes payable and up to $100,000 of interest to pay liquidation expenses), divided by the number of the then-outstanding Public Shares, which redemption will completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidation distributions, if any); and (iii) as promptly as reasonably possible following such redemption, subject to the approval of OAC’s remaining shareholders and the Board, liquidate and dissolve, subject in each case to OAC’s obligations under Cayman Islands law to provide for claims of creditors and other requirements of applicable law. There will be no distribution from the Trust Account with respect to OAC’s Warrants (as defined below), which will expire worthless in the event OAC dissolves and liquidates the Trust Account.

In the event of a liquidation, the Sponsor will not receive any monies held in the Trust Account as a result of its ownership of 5,383,739 Ordinary Shares and 116,796 Private Placement Warrants. As a consequence, a liquidating distribution will be made only with respect to the Public Shares.

TO EXERCISE YOUR REDEMPTION RIGHTS, YOU MUST DEMAND IN WRITING THAT YOUR CLASS A ORDINARY SHARES ARE REDEEMED FOR A PRO RATA PORTION OF THE FUNDS HELD IN THE TRUST ACCOUNT AND TENDER YOUR SHARES TO OAC’S TRANSFER AGENT AT LEAST TWO BUSINESS DAYS PRIOR TO THE INITIALLY SCHEDULED DATE OF THE SHAREHOLDER MEETING. IN ORDER TO EXERCISE YOUR REDEMPTION RIGHT, YOU NEED TO IDENTIFY YOURSELF AS A BENEFICIAL HOLDER AND PROVIDE YOUR LEGAL NAME, PHONE NUMBER AND ADDRESS IN YOUR WRITTEN DEMAND. YOU MAY TENDER YOUR SHARES BY EITHER TENDERING OR DELIVERING YOUR SHARES (AND SHARE CERTIFICATES (IF ANY) AND OTHER REDEMPTION FORMS) TO THE TRANSFER AGENT OR BY TENDERING OR DELIVERING YOUR SHARES (AND SHARE CERTIFICATES (IF ANY) AND OTHER REDEMPTION FORMS) ELECTRONICALLY USING THE DEPOSITORY TRUST COMPANY’S DWAC (DEPOSIT WITHDRAWAL

AT CUSTODIAN) SYSTEM. IF YOU HOLD THE SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO WITHDRAW THE SHARES FROM YOUR ACCOUNT IN ORDER TO EXERCISE YOUR REDEMPTION RIGHTS.

Subject to the foregoing, the approval of the Extension Amendment Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of at least atwo-thirds (2/3) majority of the votes cast by the holders of Class A Ordinary Shares and Class B Ordinary Shares voting as a single class, who are present in person or represented by proxy and entitled to vote thereon, and who vote thereon, at the Shareholder Meeting.

Approval of the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of at least a majority of the votes cast by the holders of the issued Class A Ordinary Shares and Class B Ordinary Shares, voting as a single class, who are present in person or represented by proxy and entitled to vote thereon, and who vote thereon, at the Shareholder Meeting. The Adjournment Proposal will only be put forth for a vote if there are not sufficient votes to approve the Extension Amendment Proposal at the Shareholder Meeting or if the Board has determined it is otherwise necessary.

Record holders of Ordinary Shares at the close of business on September 22, 2026 (the “Record Date”) are entitled to vote or have their votes cast at the Shareholder Meeting. On the Record Date, there were 19,783,010 issued and outstanding Class A Ordinary Shares (including 583,981 non-redeemable private placement Class A Ordinary Shares) and 4,799,758 issued and outstanding Class B Ordinary Shares. OAC’s Warrants do not have voting rights.

The Sponsor intends to vote all of its Ordinary Shares in favor of the proposals being presented at the Shareholder Meeting. The Sponsor’s shares will be excluded from the pro rata calculation used to determine theper-share redemption price. As of the date of the accompanying proxy statement, the Sponsor holds approximately 21.9% of the issued and outstanding Ordinary Shares and OAC’s officers and directors have not purchased any Public Shares, but may do so at any time. As a result, in addition to the Sponsor, (i) approval of the Extension Amendment Proposal will require the affirmative vote of at least 11,004,774 Ordinary Shares held by public shareholders (or approximately 57.3% of the Class A Ordinary Shares) if all Ordinary Shares are represented at the Shareholder Meeting and cast votes, and the affirmative vote of at least 79,099 Ordinary Shares held by public shareholders (or approximately 0.4% of the Class A Ordinary Shares) if only such shares as are required to establish a quorum are represented at the Shareholder Meeting and cast votes; and (ii) approval of the Adjournment Proposal will require the affirmative vote of at least 6,907,646 Ordinary Shares held by public shareholders (or approximately 36% of the Class A Ordinary Shares) if all Ordinary Shares are represented at the Shareholder Meeting and cast votes, and the affirmative vote of no Ordinary Shares held by public shareholders if only such shares as are required to establish a quorum are represented at the Shareholder Meeting and cast votes.

The accompanying proxy statement contains important information about the Shareholder Meeting, the Extension Amendment Proposal and the Adjournment Proposal. Whether or not you plan to attend the Shareholder Meeting, OAC urges you to read this material carefully and vote your shares.

The proxy statement mailed to you is also accompanied by OAC’s Annual Report on Form 10-K for the year ended December 31, 2025. Each of such documents is also available on the SEC’s website,* *

at: http://www.sec.gov.

The accompanying proxy statement is dated October 2, 2026, and is first being mailed to shareholders on or about that date.

By Order of the Board of Directors of Oaktree Acquisition Corp. III Life Sciences

/s/ Aman Kumar

Chairman of the Board of Directors

October 2, 2026