Pinnacle Acquisition Corp

As filed with the U.S. Securities and Exchange Commission on July 22, 2026.

Registration No. 333-

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)

375 South County Road, Suite 220

Palm Beach, FL 33480

(561) 309-3447

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

Steven K. Hudson

Chief Executive Officer

375 South County Road, Suite 220

Palm Beach, FL 33480

(561) 309-3447

(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, a 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 preliminary 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 preliminary 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.

$200,000,000

20,000,000 Units

Pinnacle Acquisition Corporation is a blank check company incorporated as a Cayman Islands exempted company and incorporated for the purpose of effecting a merger, amalgamation, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses, which we refer to throughout this prospectus as our initial business combination. We have not selected any business combination target and we have not, nor has anyone on our behalf, initiated any substantive discussions, directly or indirectly, with any business combination target. Our efforts to identify a prospective initial business combination target will not be limited to a particular industry, sector or geographic region.

This is an initial public offering of our securities. Each unit has an offering price of $10.00 and consists of one Class A ordinary share and one right entitling the holder thereof to receive one-eighth (1/8) of one Class A ordinary share upon the consummation of an initial business combination.

The underwriters have a 45-day option from the date of this prospectus to purchase up to an additional 3,000,000 units to cover over-allotments, if any. No fractional shares will be issued upon conversion of any rights. As a result, a rights holder must have 8 rights in order to receive one Class A ordinary share at the closing of our initial business combination.

We will provide our public shareholders with the opportunity to redeem, regardless of whether they abstain, vote for, or vote against, our initial business combination, all or a portion of their Class A ordinary shares that are sold as part of the units in this offering, which we refer to collectively as our public shares, upon 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 (net of taxes), divided by the number of then issued and outstanding public shares, subject to the limitations and on the conditions described herein. See “Summary — The Offering — Redemption rights for public shareholders upon completion of our initial business combination” and “Summary — The Offering — Redemption of public shares and distribution and liquidation if no initial business combination” for more information.

Notwithstanding the foregoing redemption rights, if we seek shareholder approval of our initial business combination and we do not conduct redemptions in connection with our initial business combination pursuant to the tender offer rules, our amended and restated memorandum and articles of association provide that a public shareholder, together with any affiliate of such shareholder 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 shares with respect to more than an aggregate of 15% of the shares sold in this offering without our prior consent. However, we would not be restricting our shareholders’ ability to vote all of their shares (including all shares held by those shareholders that hold more than 15% of the shares sold in this offering) for or against our initial business combination. See “Summary — The Offering — Limitation on redemption rights of shareholders holding 15% or more of the shares sold in this offering if we hold shareholder vote” for further discussion on certain limitations on redemption rights.

Our sponsor, PAC Sponsor, LLC, has agreed to purchase an aggregate of 225,000 private placement units (whether or not the underwriters’ over-allotment option is exercised), at a price of $10.00 per unit, or $2,250,000 in the aggregate (whether or not the underwriters’ over-allotment option is exercised), in a private placement that will close simultaneously with the closing of this offering. We refer to these units throughout this prospectus as the private placement units. Each private placement unit consists of one Class A ordinary share and one right entitled the holder thereof to receive one-eighth (1/8) of one Class A ordinary share upon the consummation of an initial business combination. Each private placement share included in each private placement unit will not have any redemption rights or be entitled to liquidating distributions from the trust account if we fail to consummate an initial business combination. See “Summary — Sponsor Information,” “The Offering — Private placement units,” “The Offering — Transfer restrictions on private placement units,” “Management’s Discussion and Analysis of Financial Condition and Results of Operation — Related Party Transactions,” “Principal Shareholders — Restrictions on Transfers of Founder Shares and Private Placement Units,” “Principal Shareholders — Registration Rights,” “Certain Relationships and Related Party Transactions” and “Description of Securities — Private Placement Units” for more information.

Steven K. Hudson, our Chairman and Chief Executive Officer, and Andrew Rechtschaffen, our director nominee, have each expressed an interest in purchasing up to $10,000,000 of the units in this offering ($20,000,000 in total, or 2,000,000 units) at the offering price, whether or not the underwriters’ over-allotment option is exercised. Such amount would represent 10.0% of the units to be sold in this offering (assuming the underwriters’ over-allotment option is not exercised). Units sold in this offering that are purchased by Mr. Hudson and Mr. Rechtschaffen would be subject to certain resale restrictions. Because these expressions of interest are not binding agreements or commitments to purchase, each of Mr. Hudson and Mr. Rechtschaffen may determine to purchase fewer or no units in this offering. The underwriters have full discretion to allocate the units in this offering to investors and may determine to sell fewer units to Mr. Hudson and Mr. Rechtschaffen, or no units at all. The underwriters will receive the same upfront discounts and commissions and deferred underwriting commissions on units purchased by Mr. Hudson and Mr. Rechtschaffen, if any, as it will on the other units sold to the public in this offering. There can be no assurance that Mr. Hudson and/or Mr. Rechtschaffen will acquire any units in this offering or as to the amount they will retain. Depending on how many units are purchased by Mr. Hudson and Mr. Rechtschaffen, the post-offering trading volume, volatility and liquidity of our securities may be reduced relative to what they would have been had the units been more widely offered and sold to other public investors, and the trading price of our Class A ordinary shares could be adversely affected. Regardless of the number of units Mr. Hudson and Mr. Rechtschaffen purchase, they will have a conflict of interest in determining whether a particular target business is an appropriate business with which to effectuate our initial business combination. In addition, Mr. Hudson and Mr. Rechtschaffen potentially will have different interests than our other public shareholders in approving our initial business combination and otherwise in exercising their rights as public shareholders because of the sponsor’s ownership (and their indirect ownership) of founder shares, which will incentivize them to act in a manner that may protect their interests in the founder shares. We do not expect a purchase of units by Mr. Hudson and Mr. Rechtschaffen to have a negative impact on our ability to meet NYSE listing eligibility requirements. See “Risk Factors — Participation in this offering by Mr. Hudson and Mr. Rechtschaffen could reduce the public float for our Class A ordinary shares and adversely affect the trading price of our Class A ordinary shares.”

On April 7, 2026, our sponsor paid $25,000, or approximately $0.0035 per share, to cover certain of our offering costs in exchange for 7,187,500 founder shares. On July 21, 2026, the Sponsor surrendered 1,437,500 founder shares for no consideration and now holds 5,750,000 founder shares. Up to 750,000 of the founder shares will be forfeited to us for no consideration after the closing of this offering depending on the extent to which the underwriters’ over-allotment option is exercised. The founder shares will automatically convert into Class A ordinary shares concurrently with or immediately following the consummation of our initial business combination, or earlier at the option of the holders thereof on a one-for-one basis, subject to the adjustments described herein. If we increase or decrease the size of the offering, we will effect a share capitalization or a share repurchase or redemption or other appropriate mechanism, as applicable, with respect to our Class B 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, on an as-converted basis, at 20% of our issued and outstanding ordinary shares upon the consummation of this offering (not including the private placement shares). The Class A ordinary shares issuable in connection with the conversion of the Class B ordinary shares may result in material dilution to our public shareholders due to the anti-dilution rights of our Class B ordinary shares that may result in an issuance of Class A ordinary shares on a greater than one-to-one basis upon conversion. Public shareholders will experience additional dilution from the issuance of the private placement shares underlying the private placement units (including private placement shares underlying private placement units issued upon conversion of working capital loans, if any such loans are converted into private placement units), as well as from the conversion of the private placement rights underlying any private placement units into private placement shares. Prior to the closing of our initial business combination, only holders of our Class B ordinary shares (i) will have the right to vote to appoint and remove directors prior to or in connection with the completion of our initial business combination and (ii) will be entitled to vote on continuing our company in a jurisdiction outside the Cayman Islands (including any special resolution required to amend our constitutional documents or to adopt new constitutional documents, in each case, as a result of our approving a transfer by way of continuation in a jurisdiction outside the Cayman Islands). On any other matters submitted to a vote of our shareholders prior to or in connection with the completion of our initial business combination, holders of the Class B ordinary shares and holders of the Class A ordinary shares will vote together as a single class, except as required by law. See “Summary — The Offering — Founder Shares,” “Summary — The Offering — Transfer Restrictions on Founder Shares,” “Summary — The Offering — Founder Shares Conversion and Anti-Dilution Rights,” “Summary — The Offering — Appointment and Removal of Directors and Continuing the Company Outside of the Cayman Islands; Voting Rights,” “Summary — Sponsor Information” and “Description of Securities — Founder Shares” for further discussion on our sponsor’s and our affiliates’ securities.

We are not prohibited from paying any fees (including advisory fees, finder’s fees, consulting fees or success fees) and reimbursements or cash payments to our sponsor, officers, directors or advisors, or our or their affiliates, for services rendered to us prior to or in connection with the completion of our initial business combination, including payment of consulting, legal, success or finder’s fees to our independent directors or advisors, or their respective affiliates, in connection with the consummation of our initial business combination. Prior to the closing of this offering, our sponsor agreed to loan us up to $300,000 to be used for a portion of the expenses of this offering. Any outstanding amount of this loan will be repaid at the earlier of December 31, 2026 or the closing of this offering. In order to fund working capital deficiencies or finance transaction costs in connection with an intended initial business combination, our sponsor or an affiliate of our sponsor or certain of our officers and directors may, but are not obligated to, loan us additional funds as may be required. If we complete our initial business combination, we would repay such loaned amounts. In the event that our initial business combination does not close, no proceeds from our trust account would be used to repay such loaned amounts. In the event that following this offering we obtain working capital loans from such persons to fund working capital or to finance transaction costs related to our initial business combination, up to $1,500,000 of such working capital loans may be convertible into units of the post-business combination entity at a price of $10.00 per unit at the option of the lender, which would result in the lender receiving an additional 150,000 private Class A ordinary shares and 150,000 private placement rights and which could materially dilute our public shareholders. Further, we may engage our sponsor or an affiliate of our sponsor as an advisor or otherwise in connection with our initial business combination and certain other transactions and pay such person or entity a salary or fee in an amount that constitutes a market standard for comparable transactions. We may also reimburse our sponsor for any out-of-pocket expenses related to identifying, investigating, negotiating and completing an initial business combination. Moreover, commencing on the date that our securities are first listed on the New York Stock Exchange (“NYSE”) through the earlier of consummation of our initial business combination and our liquidation, we intend to reimburse our sponsor, or an affiliate of our sponsor, for accounting, bookkeeping, office space, IT support, research, professional, secretarial and administrative services provided to us in an amount fixed at $10,000 per month. Our audit committee will review on a quarterly basis all payments that were made to our sponsor, directors or officers, or our or their affiliates. See “Summary — Sponsor Information,” “Summary — Limited payments to insiders,” “Use of Proceeds,” “Management’s Discussion and Analysis of Financial Condition and Results of Operation — Related Party Transactions” and “Certain Relationships and Related Party Transactions” for further discussion on compensation paid or to be paid to our sponsor and its affiliates.

As more fully discussed in “Management — Conflicts of Interest,” each of our officers and directors presently has, and any of them in the future may have additional, fiduciary, contractual or other obligations or duties to one or more other entities pursuant to which such officer or director is or will be required to present a business combination opportunity to such entities. 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 21 months from the closing of this offering, or by such earlier liquidation date as our board of directors may approve, the founder shares and private placement units may have no value to the holder, 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. 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 was included by a target business as a condition to any agreement with respect to our initial business combination. As a result, there may be actual or potential material conflicts of interest between members of our management team, our sponsor and its affiliates on one hand, and purchasers in this offering on the other. See “Summary — The Offering — Sponsor Information,” “Summary — The Offering — Transfer Restrictions on Founder Shares,” “Summary — The Offering — Founder Shares Conversion and Anti-Dilution Rights,”and “Risk Factors — Risks Relating to our Management Team — 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 our sponsor is likely to make a substantial profit on its investment in us in the event we consummate an initial business combination, even if the business combination causes the trading price of our ordinary shares to materially decline,” for further discussion on our sponsor’s and our affiliates’ securities and compensation.

We have until the date that is 21 months from the closing of this offering, or until such earlier liquidation date as our board of directors may approve, to consummate our initial business combination. If we anticipate that we may be unable to consummate our initial business combination within such time period and we wish to further extend the date by which we must consummate our initial business combination, we will seek shareholder approval to amend our amended and restated memorandum and articles of association to extend the date by which we must consummate our initial business combination, and holders of public shares will be offered an opportunity to redeem their shares at a per share price, payable in cash, equal to the aggregate amount then on deposit in the trust account, including interest earned thereon (net of taxes), divided by the number of then issued and outstanding public shares, subject to applicable law. There are no limitations as to the duration of an extension or the number of times the completion window may be extended by shareholders via an amendment to our amended and restated memorandum and articles of association; however, such amendment to our amended and restated memorandum and articles of association may include limitations on the duration of the extension, the number of possible extensions, requirements for additional payments to the trust in connection with an extension and other potential terms for consideration by our shareholders. If we are unable to complete our initial business combination within 21 months from the closing of this offering, or by such earlier liquidation date as our board of directors may approve, 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 thereon (net of taxes and less up to $100,000 of interest income to pay liquidation and dissolution expenses), divided by the number of then issued and outstanding public shares, subject to applicable law and certain conditions as further described herein.

If we have not completed our initial business combination within the time period described above (including any extensions), we will cease all operations except for the purpose of winding up, redeem the public shares, and, subject to the approval of our remaining shareholders and our board of directors, liquidate and dissolve, subject in each case to our obligations under Cayman Islands law to provide for claims of creditors and the requirements of other applicable law. There will be no redemption rights or liquidating distributions with respect to our rights, which may have no value to the holder if we fail to complete our initial business combination within the completion window. See “Summary — The Offering — Redemption of public shares and distribution and liquidation if no initial business combination.”

Currently, there is no public market for our units, Class A ordinary shares or rights. We intend to apply to have our units listed on NYSE, under the symbol “PNAQ.U”, on or promptly after the date of this prospectus. We cannot guarantee that our securities will be approved for listing on NYSE. We expect the Class A ordinary shares and rights comprising the units to begin separate trading on the 52 nd day following the date of this prospectus unless Santander US Capital Markets LLC, the representative of the underwriters, informs us of its decision to allow earlier separate trading, subject to our satisfaction of certain conditions as described further herein. Once the securities comprising the units begin separate trading, we expect that the Class A ordinary shares and rights will be listed on NYSE under the symbols “PNAQ” and “PNAQ.RT”, respectively.

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 45 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, is being or may be made to the public in the Cayman Islands to subscribe for any of our securities.

(1) Includes $250,000 (such amount to remain unchanged in the event the underwriters’ over-allotment option is exercised) payable to the underwriters upon the closing of this offering. Also includes $0.30 per unit on all units sold ($6,000,000 in the aggregate or up to $6,900,000 in the aggregate if the underwriters’ over-allotment option is exercised) payable to

the underwriters for deferred underwriting commissions to be deposited into a trust account located in the United States and released to the underwriters only upon the completion of an initial business combination. Such deferred underwriting commissions will not be payable with respect to any shares redeemed in connection with an initial business combination. See also “Underwriting” for a description of compensation and other items of value payable to the underwriters.

In addition to the underwriting discounts and commissions, we will also engage the underwriters to provide advisory services from time to time. As compensation for the services provided under the engagement letter, we will agree to pay the underwriters an advisory fee equal to 3% of the gross proceeds raised in the IPO, payable upon closing of our initial business combination ($6,000,000 in the aggregate or up to $6,900,000 in the aggregate if the underwriters’ over-allotment option is exercised). We will also agree to indemnify the underwriters and their affiliates in connection with their role in providing the advisory services. No advisory fees will be payable to the underwriters in the event we do not complete our initial business combination, and the advisory fee payable upon our initial business combination will not include any amounts in respect of interest.

Of the proceeds we receive from this offering and the sale of the private placement units described in this prospectus, $200.0 million, or up to $230.0 million if the underwriters’ over-allotment option is exercised ($10.00 per unit in either case), will be placed into a U.S.-based trust account with Continental Stock Transfer & Trust Company acting as trustee.

Because our sponsor acquired the founder shares at a nominal price, our public shareholders will incur an immediate and substantial dilution upon the closing of this offering, assuming no value is ascribed to the rights included in the units. Further, the Class A ordinary shares issuable in connection with the conversion of the founder shares, and any private placement shares of the post-business combination entity issuable in connection with the conversion of up to $1,500,000 of loans from our sponsor, members of our management team or their affiliates or other third parties, at a price of $10.00 per unit, may result in material dilution to our public shareholders. Such dilution could materially increase to the extent that the anti-dilution provision of the founder shares results in the issuance of Class A ordinary shares on a greater than one-to-one basis upon conversion of the founder shares concurrently with or immediately following our initial business combination to maintain the number of founder shares at 20% of the total number of issued and outstanding ordinary shares. See “Summary — The Offering — Founder Shares Conversion and Anti-Dilution Rights.” In addition, our board of directors is not currently contemplating and does not anticipate approving any share capitalizations in the foreseeable future, except if we increase the size of this offering, in which case we will effect a share capitalization or other appropriate mechanism immediately prior to the consummation of this offering in an amount necessary to maintain the number of founder shares at 20% of the total number of our issued and outstanding ordinary shares upon the consummation of this offering (not including the private placement shares), which may result in further material dilution to our public shareholders. See the sections titled “Dividend Policy,” “Risk Factors — Risks Relating to our Securities — 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 our sponsor is likely to make a substantial profit on its investment in us in the event we consummate an initial business combination, even if the business combination causes the trading price of our ordinary shares to materially decline” and “Risk Factors — Risks Relating to our Search for, and Consummation of or Inability to Consummate, a Business Combination — We may issue additional Class A ordinary shares or preference shares to complete our initial business combination or under an employee incentive plan after completion of our initial business combination. We may also issue Class A ordinary shares upon the conversion of the founder shares at a ratio greater thanone-to-one concurrently with or immediately following the consummation of our initial business combination as a result of theanti-dilution provisions contained therein. Any such issuances would dilute the interest of our shareholders and likely present other risks.”

The following table illustrates the difference between the deemed offering price of $10.00 per unit and our net tangible book value per share (“NTBV”), as adjusted to give effect to this offering, including the structure of the underwriting commissions, and assuming the redemption of our public shares at varying levels and the exercise in full and no exercise of the over-allotment option. See the section titled“Dilution” for more information.

Our sponsor and members of our management team will directly or indirectly own our securities following this offering, and accordingly, they 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. Additionally, each of our officers and directors presently has, and any of them in the future may have additional, fiduciary, contractual or other obligations or duties to one or more other entities pursuant to which such officer or director is or will be required to present a business combination opportunity to such entities. As a result, there may be actual or potential conflicts of interest between our sponsor and its affiliates on one hand, and purchasers in this offering on the other. See the sections titled “Summary — Conflicts of Interest”, “Proposed Business — Acquisition Process” and “Management — Conflicts of Interest” for more information.

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

Joint Book-Running Managers

, 2026