JATT III Acquisition Corp

As filed with the Securities and Exchange Commission on August 7, 2026.

Registration No. [ ]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

153 Central Avenue

C/O 56

Westfield, NJ 07091

201-688-0364

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Nicholas Fernandez

Chief Financial Officer

153 Central Avenue

C/O 56

Westfield, NJ 07091

201-688-0364

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this registration statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.☐

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED AUGUST 7, 2026

PRELIMINARY PROSPECTUS

$60,000,000

6,000,000 Ordinary Shares

JATT III Acquisition Corp is a blank check company incorporated as a Cayman Islands exempted company with limited liability for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses, which we refer to as our initial business combination (the “Company”). We will have (i) 24 months from the closing of this offering or such earlier date as our board of directors may approve, or (ii) such other time period pursuant to an amendment to our articles to complete our initial business combination (such period, the “completion window”). We have not selected any specific business combination target and we have not, nor has anyone on our behalf, engaged in any substantive discussions, directly or indirectly, with any business combination target with respect to an initial business combination with us.

This is an initial public offering of our ordinary shares, par value $0.0001 per share, which we refer to as our public shares, at an initial public offering price of $10.00. The underwriters have a 45-day option from the date of this prospectus to purchase up to an additional 900,000 ordinary shares to cover over-allotments, if any. Unlike certain other special purpose acquisition company initial public offerings (“SPAC IPOs”), investors in this offering will not receive warrants that would become exercisable following completion of our initial business combination.

We will provide our public shareholders with the opportunity to redeem all or a portion of their ordinary shares that were sold as part of this offering, which we refer to collectively as our public shares, in connection with the completion of our initial business combination at a per-share price, payable in cash, equal to the aggregate amount then on deposit in the trust account described below as of two business days prior to the consummation of our initial business combination, including interest earned on the funds held in the trust account (less taxes paid or payable (other than excise or similar taxes)), divided by the number of then issued and outstanding public shares, subject to the limitations and on the conditions described herein. As further described in this prospectus, our articles provide that a public shareholder, together with any affiliate or any other person with whom such shareholder is acting in concert or as a “group” (as defined under Section 13 of the Securities Exchange Act of 1934, as amended, the “Exchange Act”), will be restricted from redeeming its public shares with respect to more than an aggregate of 20% of the public shares sold in this offering, without our prior consent. Each public shareholder may elect to redeem their public shares irrespective of whether they vote for or against an initial business combination, or whether they do not vote or abstain from voting on the initial business combination, and regardless of whether they hold public shares on the record date established in connection with our initial business combination.

If we are unable to complete our initial business combination within the completion window, we will redeem 100% of 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 earned on the funds held in the trust account (less taxes paid or payable (other than excise or similar taxes) and up to $100,000 of interest to pay dissolution expenses), divided by the number of then issued and outstanding public shares, subject to applicable law and certain limitations and on the conditions as further described herein. We may seek shareholder approval to amend our articles to extend the date by which we must consummate our initial business combination. If we seek shareholder approval for an extension, holders of our public shares will be offered an opportunity to redeem their shares upon approval of such extension, regardless of whether they abstain, vote in favor of or vote against such extension.

Our sponsor, JATT Ventures III L.P., a Cayman Islands exempted limited partnership formed for the purpose of investing in us (the “sponsor”), acting by its general partner, JATT Ventures III Ltd, has committed to purchase an aggregate of 225,000 ordinary shares (or 234,000 shares if the underwriters’ over-allotment option is exercised in full), at a price of $10.00 per share in a private placement for an aggregate purchase price of $2,250,000 in the aggregate (or $2,340,000 if the underwriters’ over-allotment option is exercised in full), that will close simultaneously with the closing of this offering. These ordinary shares, which we refer to as the private placement shares, are identical to the ordinary shares sold in this offering, subject to certain limited exceptions as described in this prospectus.

Our initial shareholders, which include our sponsor, currently own an aggregate of 1,725,000 ordinary shares (the “founder shares”), up to 225,000 of which will be surrendered to us for no consideration after the closing of this offering depending on the extent to which the underwriters’ over-allotment option is exercised. See the sections entitled “Summary — Our Sponsor” on page 12, “Summary — The Offering — Founder shares” on page 17, “Summary — The Offering — Voting” on page 19, “Risk Factors — Risks Relating to our Search for, and Consummation of, or Inability to Consummate, a Business Combination — The ability of our public shareholders to exercise redemption rights with respect to a large number of our shares and the amount of deferred underwriting compensation may not allow us to complete the most desirable business combination or optimize our capital structure, and may substantially dilute your investment in us” on page 39, “Risk Factors — Risks Relating to our Search for, and Consummation of, or Inability to Consummate, a Business Combinationon page 38, “Dilution” on page 84 and “Proposed Business — Our Sponsor” on page 103 for more information.

Because our sponsor acquired the founder shares at a nominal price of $25,000, or approximately $0.0145 per share, our public shareholders will incur an immediate and material dilution upon the closing of this offering. Our public shareholders may experience additional dilution if we increase the size of the offering pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the “Securities Act”) and effect with our sponsor a share dividend or other appropriate mechanism, as applicable, with respect to our ordinary shares immediately prior to the consummation of the offering in such amount as to maintain the ownership of founder shares by our initial shareholders at 20% of our issued and outstanding ordinary shares upon the consummation of this offering. See the section titled “Risk Factors — The nominal purchase price paid by our sponsor for the founder shares may result in significant dilution to the implied value of your public shares upon the consummation of our initial business combination, and the value of the founder shares following completion of our initial business combination is likely to be substantially higher than the nominal price paid for them, even if the business combination causes the trading price of our ordinary shares to materially decline.”Prior to closing of this offering, our management team will receive indirect interests in founder shares through membership interests in our sponsor, including (i) to our Chief Executive Officer, Dr. Someit Sidhu 150,000 founder shares for his services, (ii) to our Chief Financial Officer, Mr. Nicholas Fernandez 50,000 founder shares for his services, (iii) to each of our independent directors 25,000 founder shares for their board services, and (iv) to an independent consultant of the Company 25,000 founder shares for his services in connection to this offering. Our management team may also purchase additional membership interests in our sponsor to receive indirect interest in ordinary shares held by our sponsor. We will also pay our sponsor for officer compensation and administrative services provided to members of our management team an amount equal to $20,000 per month. Our sponsor may loan us up to $300,000 under an unsecured, non-interest bearing promissory note for offering-related and organizational expenses. The loan is due at the closing of this offering and is anticipated to be repaid upon completion of this offering out of the $550,000 of offering proceeds that has been allocated for the payment of offering expenses other than underwriting commissions. Our sponsor or an affiliate of our sponsor or certain of our officers and directors may loan us funds to finance transaction costs in connection with an intended initial business combination. Up to $1,500,000 of such loans may be convertible into private placement shares of the post-business combination entity at a price of $10.00 per share at the option of the lender. The issuance of such shares may result in material dilution to our public shareholders. See the section titled “Summary — Our Sponsor” for more information regarding, among other things, the amount of compensation and securities received or to be received by our sponsor, its affiliates and our officers and directors.

The following table illustrates the difference between the public offering price and our net tangible book value per share, as adjusted to reflect various potential redemption levels that may occur in connection with the closing of our initial business combination, which we refer to as Adjusted NTBVPS, on a pro forma basis to give effect to this offering and the issuance of the private placement shares, assuming no exercise of the over-allotment option and exercise of the over-allotment option in full. Adjusted NTBVPS excludes the effect of the consummation of our initial business combination or any related transactions or expenses. See the section titled “Dilution” for more information.

Members of our management team and board of directors will directly or indirectly own founder shares and/or private placement shares following this offering and, accordingly, may have a conflict of interest in determining whether a particular target business is an appropriate business with which to effectuate our initial business combination and in negotiating or accepting the terms of the transaction because of their financial interest in completing an initial business combination within the completion window. Further, each of our officers and directors may have a conflict of interest with respect to evaluating a particular business combination if the retention or resignation of any such officers and directors were to be included by a target business as a condition to any agreement with respect to our initial business combination. The low price that our sponsor, executive officers and directors (directly or indirectly) paid for the founder shares creates an incentive whereby our officers and directors could potentially make a substantial profit even if we select an acquisition target that subsequently declines in value and is unprofitable for public shareholders. If we are unable to complete our initial business combination within the completion window, the founder shares may expire worthless, except to the extent they receive liquidating distributions from assets outside the trust account, which could create an incentive for our sponsor, executive officers and directors to complete a transaction even if we select an acquisition target that subsequently declines in value and is unprofitable for public shareholders. Additionally, each of our officers and directors presently has, and any of them in the future may have additional, fiduciary or contractual obligations to another entity pursuant to which such officer or director is or will be required to present a business combination opportunity to such entity. Accordingly, there may be actual or potential material conflicts of interest between our sponsor, its affiliates or promoters on the one hand, and the investors in this offering on the other hand. See the sections titled “Proposed Business — Sourcing of Potential Business Combination Targets” and “Management — Conflicts of Interest.”

Of the gross proceeds we receive from this offering and the sale of the private placement shares described in this prospectus, $60,000,000, or $69,000,000 if the underwriters’ over-allotment option is exercised in full ($10.00 per share in either case), after deducting $600,000 in underwriting discounts and commissions payable upon the closing of this offering (or $690,000 if the underwriters’ over-allotment option is exercised in full) and an aggregate of approximately $550,000 to pay fees and expenses in connection with the closing of this offering and approximately $1,100,000 for working capital following the closing of this offering, will be deposited into a trust account located in the United States with Odyssey Transfer and Trust Company acting as trustee and held only (i) uninvested as cash, (ii) in an interest-bearing or non-interest bearing demand deposit account at a U.S. chartered commercial bank with consolidated assets of $100 billion or more selected by the trustee that is reasonably satisfactory to us, or (iii) invested only in U.S. government securities, within the meaning of Section 2(a)(16) of the Investment Company Act of 1940, as amended (the “Investment Company Act”) with a maturity of 185 days or less, or in money market funds meeting certain conditions under Rule 2a-7 under the Investment Company Act, which invest only in direct U.S. government treasury obligations. To mitigate the risk that we might be deemed to be an investment company for purposes of the Investment Company Act, which risk increases the longer we hold investments in the trust account, we may, at any time, instruct the trustee to liquidate the investments held in the trust account and instead to hold the funds in the trust account uninvested in cash or in an interest-bearing or non-interest-bearing demand deposit account. For more information about the risk of the company being considered to be operating as an unregistered investment company, see “Risk Factors — Risks Relating to our Search for, Consummation of, or Inability to Consummate, a Business Combination — If we are deemed to be an investment company under the Investment Company Act, we may be required to institute burdensome compliance requirements and our activities may be restricted, which may make it difficult for us to complete our initial business combination or force us to abandon our efforts to complete an initial business combination.”

AI Biotechnology LLC (“AI Biotechnology”), an affiliate of Access Industries, Inc., has indicated an interest to purchase up to an aggregate of $30,000,000 of our ordinary shares in a private placement that would occur concurrently with the consummation of our initial business combination. However, because indications of interest are not binding agreements or commitments to purchase, AI Biotechnology may ultimately elect to purchase more, fewer or no shares. We are also under no obligation to sell any shares to AI Biotechnology. As such, there can be no assurance that AI Biotechnology will acquire any shares in connection with our initial business combination or otherwise. Any investment by AI Biotechnology or its affiliated entities and persons would be made on terms and conditions determined at the time of the business combination and may be different from the terms and conditions on which shares are sold to other investors in any private placement.

In addition, Vianti Capital Fund I, L.P. and/or one or more affiliated investment vehicles designated by its investment manager (collectively, “Vianti”) has indicated a non-binding interest to purchase up to an aggregate of $15,000,000 of our ordinary shares in a private placement that may occur concurrently with the consummation of our initial business combination. However, because this indication of interest is not a binding agreement, offer or commitment to purchase, Vianti may, in its sole discretion, elect to purchase more, fewer or no shares and may modify or withdraw its indication of interest at any time, for any reason or no reason, without liability. We are under no obligation to sell any shares to Vianti. Accordingly, there can be no assurance that Vianti will acquire any shares in connection with our initial business combination or otherwise. Any investment by Vianti would be subject to, among other things, its satisfactory completion of due diligence, the approval of its investment committee, the availability of capital, compliance with its governing documents and applicable law, and the negotiation and execution of definitive agreements acceptable to Vianti, in each case as determined by Vianti in its sole discretion at the time of the proposed private placement. Any such investment would be made on terms and conditions determined at such time, which may differ from the terms and conditions on which shares are sold to other investors in any private placement.

If we sell shares to AI Biotechnology or Vianti (or any other investor) in connection with our initial business combination, the equity interest of investors in this offering in the combined company may be diluted and the market prices for our securities may be adversely affected. In addition, if the per share trading price of our ordinary shares is greater than the price per share paid in the private placement, the private placement will result in value dilution to you, in addition to the immediate dilution that you will experience in connection with the consummation of this offering. See the section entitled “Dilution” for further information.

Currently, there is no public market for our ordinary shares. We intend to apply to have our shares listed on The Nasdaq Capital Market, or Nasdaq, under the symbol “JTTT”. We expect that our shares will be listed on Nasdaq on or promptly after the date of this prospectus. We cannot guarantee that our securities will be approved for listing on Nasdaq.

We are an “emerging growth company” and a “smaller reporting company” under applicable federal securities laws and will be subject to reduced public company reporting requirements. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 38 for a discussion of information that should be considered in connection with an investment in our securities. Investors will not be entitled to protections normally afforded to investors in Rule 419 blank check offerings.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense. No offer or invitation, whether directly or indirectly, may be made to the public in the Cayman Islands to subscribe for our securities.

The underwriters are offering the ordinary shares for sale on a firm commitment basis. The underwriters expect to deliver the shares to the purchasers on or about , 2026.

Sole Bookrunning Manager

Guggenheim Securities

, 2026

TABLE OF CONTENTS

We have not, and the underwriters have not, authorized anyone to provide you with information that is different from or inconsistent with that contained in this prospectus. We are not, and the underwriters are not, making an offer to sell securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front of this prospectus.

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