Launch One Acquisition Corp.

The extraordinary general meeting in lieu of an annual general meeting (the “Meeting”) of Launch One Acquisition Corp. (“we,” “us,” “our” or the “Company”) will be held at 10:00 a.m. Eastern Time on July 7, 2026 at the offices of Ellenoff Grossman & Schole LLP, located at 1345 Avenue of the Americas, 11 th Fl., New York, NY 10105, or at such other time, on such other date and at such other place to which the meeting may be postponed or adjourned, or to attend virtually via the Internet. You will be able to attend the Meeting online, vote, view the list of shareholders entitled to vote at the Meeting and submit your questions during the Meeting by visiting https://www.cstproxy.com/launchoneacquisitioncorp/2026 or by phone dialing within the U.S. and Canada 800-450-7155 (toll-free) or outside of the U.S. and Canada +1 857-999-9155 (standard rates apply) and entering the conference identification number 2853182#. The sole purpose of the Meeting is to consider and vote upon the following proposals:

• a proposal to amend, by way of special resolution, the Company’s amended and restated memorandum and articles of association (the “Articles”) pursuant to an amendment to the Articles in the form set forth in Annex A to the accompanying Proxy Statement (the “Extension Amendment” and, such proposal, the “Extension Amendment Proposal”) to extend the date by which the Company must (1) consummate a merger, amalgamation, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses (a “business combination”), (2) cease its operations except for the purpose of winding up if it fails to complete such business combination, and (3) redeem all of the Company’s Class A ordinary shares of par value $0.0001 per share (“Class A ordinary shares”) included as part of the units sold in the Company’s initial public offering that was consummated on July 15, 2024 (the “IPO”), from July 15, 2026 to January 15, 2027 (the “Extended Date”);

• a proposal to ratify, by way of ordinary resolution, the selection by the Board’s audit committee of WithumSmith+Brown, PC (“Withum”) to serve as the Company’s independent registered public accounting firm for the year ending December 31, 2026 (the “Auditor Ratification Proposal”); and

• a proposal to approve, by way of ordinary resolution, the adjournment of the Meeting to a later date or dates, (i) to permit further solicitation and vote of proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the Extension Amendment Proposal or (ii) where the Board has determined it is otherwise necessary (the “Adjournment Proposal”). The Adjournment Proposal will only be presented at the Meeting if there are not sufficient votes to approve the Extension Amendment Proposal or the Auditor Ratification Proposal.

The purpose of the Extension Amendment is to allow us more time to enter into and complete a potential business combination (a “Potential Business Combination”) in case such additional time is needed. The Articles provide that we have until July 15, 2026 to complete our initial business combination. Since we have not yet entered into a definitive agreement with respect to a Potential Business Combination, our board of directors (our “board”) believes that there may not be sufficient time before July 15, 2026 to hold an extraordinary general meeting at which to conduct a vote for the shareholder approvals required in connection with a Potential Business Combination and consummate the closing of a Potential Business Combination. Accordingly, our board believes that in order for us to be able to potentially consummate a Potential Business Combination, we will need to obtain the Extension.

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

In connection with the Extension Amendment Proposal, each holder of public shares who is not our sponsor, Launch One Sponsor LLC (the “Sponsor”), a shareholder of ours immediately prior to the consummation of the IPO (“Founder”), or an Officer or Director of ours may elect to redeem their public shares upon the effectiveness of the Extension Amendment for a per-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned (which interest shall be net of taxes payable), divided by the number of Class A ordinary shares included as part of the units sold in the IPO (the “public shares”) then in issue (the “Withdrawal Amount”), subject to applicable law, and which election we refer to as the “Election.” An Election can be made regardless of whether such public shareholders vote “FOR” or “AGAINST” the Extension Amendment Proposal and an Election can also be made by public shareholders who do not vote, or do not instruct their broker or bank how to vote, at the Meeting. Holders of public shares (the “public shareholders”) may make an Election regardless of whether such public shareholders were holders as of the record date. Public shareholders other than the Sponsor, a Founder or an Officer or Director of ours who do not make the Election would be entitled to have their shares redeemed for cash if we have not completed our initial business combination by the Extended Date. In addition, regardless of whether public shareholders vote “FOR” or “AGAINST” the Extension Amendment Proposal, or do not vote, or do not instruct their broker or bank how to vote, at the Meeting, if the Extension is implemented and a public shareholder does not make an Election, they will retain the right to vote on any Potential Business Combination in the future, and the right to redeem their public shares at a per-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account as of two business days prior to the consummation of such initial business combination, including interest (which interest shall be net of taxes payable), divided by the number of then issued public shares, in the event a Potential Business Combination is completed. We are not asking you to vote on any Potential Business Combination at this time. If we enter into a Potential Business Combination, we intend to file (i) promptly thereafter a current report on Form 8-K with information about a Potential Business Combination, and (ii) in due course a separate proxy statement/prospectus pursuant to which we will seek approval of a Potential Business Combination, among other things, at a separate extraordinary general meeting. If the Extension is not approved, we may not be able to enter into, nor consummate, a Potential Business Combination. We urge you to vote at the Meeting regarding the Extension. In addition, if you elect to redeem your shares at this time in connection with the Extension, sufficient cash amounts may not remain in the Trust Account to permit the Company to satisfy a related closing condition that may be set forth in the transaction documents of a Potential Business Combination, if any. As a result, while a target company would have the right to waive any related closing condition in certain circumstances, a Potential Business Combination may not be consummated if there is not a sufficient amount of cash in the Trust Account as a result of redemptions of our shares in connection with the Extension, even if our shareholders vote to approve the Extension.

The withdrawal of funds from the Trust Account in connection with the Election will reduce the amount held in the Trust Account following the Election, and the amount remaining in the Trust Account may be only a small fraction of the approximately $249,132,955 that was in the Trust Account as of June 2, 2026. In such event, we may need to obtain additional funds to complete a Potential Business Combination, and there can be no assurance that such funds will be available on terms acceptable or at all.

If the Extension Amendment Proposal is not approved and we do not consummate our initial business combination by July 15, 2026, as contemplated by our IPO prospectus and in accordance with our Articles, we will: (1) cease all operations except for the purpose of winding up; (2) as promptly as reasonably possible but not more than 10 business days thereafter, subject to lawfully available funds, redeem the public shares, at a per-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest (less up to $100,000 of interest to pay dissolution expenses and which interest shall be net of taxes payable), divided by the number of public shares then in issue, which redemption will completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidation distributions, if any) subject to applicable law; and (3) as promptly as reasonably possible following such redemption, subject to the approval of our remaining shareholders and our board, liquidate and dissolve, subject in each case to our obligations under Cayman Islands law to provide for claims of creditors and in all cases subject to the other requirements of applicable law.

There will be no redemption rights or liquidating distributions with respect to our warrants, which will expire worthless in the event of our winding up. In the event of a liquidation, the Sponsor, holder of our Class B ordinary shares (the “founder shares” and, together with the public shares, the “shares” or “ordinary shares”), will not receive any monies held in the Trust Account as a result of its ownership of the founder shares.

Based upon the amount in the Trust Account as of June 2, 2026, which was approximately $249,132,955, we anticipate that the per-share price at which public shares will be redeemed from cash held in the Trust Account will be approximately $10.83 at the time of the Meeting. The closing price of the public shares on the Nasdaq Global Market (the “Nasdaq”) on June 5, 2026, the most recent practicable closing price prior to the mailing of this Proxy Statement, was $10.80. We cannot assure shareholders that they will be able to sell their 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 our securities when such shareholders wish to sell their shares.

Our board has fixed the close of business on May 15, 2026 as the record date for determining our shareholders entitled to receive notice of and vote at the Meeting and any adjournment thereof. Only holders of record of the ordinary shares on that date are entitled to have their votes counted at the Meeting or any adjournment thereof. On the record date of the Meeting, there were 28,750,000 ordinary shares outstanding, of which 23,000,000 were public shares and 5,750,000 were founder shares. The founder shares carry voting rights in connection with the Extension Amendment Proposal, the Auditor Ratification Proposal and the Adjournment Proposal, and we have been informed by our Sponsor, which holds all founder shares, that they intend to vote in favor of the Extension Amendment Proposal, the Auditor Ratification Proposal and the Adjournment Proposal.

Shareholders will have the opportunity to present questions to our management (the “Management”), including regarding our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, as filed with the SEC on March 27, 2026 (the “2025 Annual Report”), at the Meeting.

This Proxy Statement contains important information about the Meeting and the proposals. Please read it carefully and vote your shares.

We will pay for the entire cost of soliciting proxies. We have engaged Okapi Partners LLC (“Okapi”), to assist in the solicitation of proxies for the Meeting. We have agreed to pay Okapi a fee of $15,000. We will also reimburse Okapi for reasonable out-of-pocket expenses and will indemnify Okapi and its affiliates against certain claims, liabilities, losses, damages and expenses. In addition to these mailed proxy materials, our directors and officers may also solicit proxies in person, by telephone or by other means of communication. These parties will not be paid any additional compensation for soliciting proxies. We may also reimburse brokerage firms, banks and other agents for the cost of forwarding proxy materials to beneficial owners.

This Proxy Statement is dated June 10, 2026 and is first being mailed to shareholders on or about June 12, 2026.