FG Imperii Acquisition Corp.

As filed with the U.S. Securities and Exchange Commission on October 14, 2025

Registration No. 333-[ ]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM****S-1

REGISTRATION STATEMENT UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

104 S. Walnut Street, Unit 1A

Itasca, Illinois 60143

Tel: (847) 791-6817

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

Hassan R. Baqar

104 S. Walnut Street, Unit 1A,

Itasca, IL 60143

Tel: (847) 791-6817

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

Copies to:

Jose Santos, Esq.

Sonia Starvis Esq.

Forbes Hare

Cassia Court Camana Bay Suite 716

10 Market Street

Grand Cayman KY1-9006

Tel: (345) 943-7700

**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 contained in this preliminary prospectus is not complete and may be changed. These securities may not be sold 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 state where the offer or sale is not permitted.

20,000,000 Units

FG Imperii Acquisition Corp. is a blank check company incorporated in the Cayman Islands as an exempted company whose business purpose is to effect a merger, amalgamation, share capital exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses, which we refer to as our initial business combination. 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. Although we may acquire a business in any industry, we intend to focus our search for a target business in the financial services industry in North America.

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-half of one redeemable warrant. Each whole warrant entitles the holder thereof to purchase one Class A ordinary share at a price of $11.50 per share, subject to adjustment as described herein. Only whole warrants are exercisable. No fractional warrants will be issued upon separation of the units and only whole warrants will trade. The warrants will become exercisable on the later of 30 days after the completion of our initial business combination and 12 months from the closing of this offering, and will expire five years after the completion of our initial business combination or earlier upon redemption or our liquidation, as described herein. The underwriters have a 45-day option from the date of this prospectus to purchase up to 3,000,000 additional units to cover over-allotments, if any.

We are an “emerging growth company” under applicable federal securities laws and will be subject to reduced public company reporting requirements. No offer or invitation to subscribe for securities may be made to the public in the Cayman Islands

We will provide our public shareholders with theopportunity to redeem all or a portion of their Class A ordinary shares (up to an aggregate of 15% for each public shareholder of the shares sold in this offering, as described in more detail in this prospectus)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 (which interest shall be net of funds withdrawn for taxes payable), divided by the number of then outstanding Class A ordinary shares that were sold as part of the units in this offering, which we refer to collectively as our public shares, subject to the limitations and on the conditions described herein. If we are unable to complete our initial business combination within 24 months from the closing of this offering (or such later date as approved by the affirmative vote of the holders of a majority of the Class A ordinary shares that are voted at a shareholder meeting held to amend our amended and restated memorandum and articles of association to extend such date, voting together as a single class), 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 (which interest shall be net of funds withdrawn for taxes payable, and up to $100,000 of interest to pay dissolution expenses), divided by the number of then outstanding public shares, subject to applicable law and certain conditions as further described herein.

Our sponsor (and/or its designees) has committed to purchase from us an aggregate of (i) 275,000 units (the “private units”) at a price of $10.00 per private unit, with each private unit consisting of one Class A ordinary share (the “private shares”) and one-half of one warrant (each whole warrant, a “private warrant”) to purchase one Class A ordinary share at an exercise price of $11.50 per share by exercising a whole private warrant, and (ii) 1,000,000 warrants (“$15 Exercise Price Warrants” and, together with the private units, the “private placement securities”) at a price of $0.10 per warrant, each exercisable to purchase one Class A ordinary share at $15.00 per share, for an aggregate purchase price of $2,850,000. The $15 Exercise Price Warrants will become exercisable on the later of 30 days after the completion of our initial business combination and 12 months from the closing of this offering, and will expire five years (or ten years with respect to the $15 Exercise Price Warrants (as defined below)) after the completion of our initial business combination or earlier upon redemption or our liquidation, as described herein.These purchases will take place on a private placement basis simultaneously with the consummation of this offering.

Our initial shareholders currently own an aggregate of 5,750,000 Class B ordinary shares (which were purchased for $10,000 and which we refer to as “founder shares”) (up to 750,000 Class B ordinary shares 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, which 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. 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.

If we are unable to complete our initial business combination within the completion window, or by such earlier liquidation date as our board of directors may approve, the founder shares, private units (and the underlying securities) and the $15 Exercise Price Warrants (and the underlying securities) will be worthless, except to the extent they receive liquidating distributions from assets outside the trust account. Additionally, we will repay up to $150,000 in loans made to us by our sponsor to cover offering-related and organizational expenses and we will reimburse our sponsor an amount equal to $15,000 per month for office space, administrative and support services made available to us, as described elsewhere in this prospectus. We will repay any loans which may be made by our sponsor or an affiliate of our sponsor or certain of our directors and officers 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 units at a price of $10.00 per unit at the option of the lender. Upon consummation of this offering, we will also reimburse our sponsor, directors or officers, or our or any of their respective affiliates for any out-of-pocket expenses related to identifying, investigating and completing an initial business combination.

The following table illustrates the difference between the public offering price per unit 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 “NTBV,” on a pro forma basis to give effect to this offering and the issuance of the private units and the $15 Exercise Price Warrants, assuming no exercise of the over-allotment option and exercise of the over-allotment option in full. NTBV excludes the effect of the consummation of our initial business combination or any related transactions or expenses. See the Section entitled “Dilution” of this prospectus for additional information.

Currently, there is no public market for our units, Class A ordinary shares or warrants. We have applied to have our units listed on the Nasdaq Global Market under the symbol “FGIIU” on or promptly after the date of this prospectus. We cannot guarantee that our securities will be approved for listing on the Nasdaq Global Market. We expect the Class A ordinary shares and warrants comprising the units to begin separate trading on the 52nd day following the date of this prospectus unless ThinkEquity LLC and EarlyBirdCapital, Inc. inform us of their decision to allow earlier separate trading, subject to our satisfaction of certain conditions. Once the securities comprising the units begin separate trading, we expect that the Class A ordinary shares and warrants will be listed on the Nasdaq Global Market under the symbols “FGII” and “FGIIW,” respectively.

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.

We are an “emerging growth company” under applicable federal securities laws and will be subject to reduced public company reporting requirements.

As described in “Proposed Business — Sourcing of Potential Initial Business Combination Targets” and “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. There may beactual or potential material conflicts of interest (direct and indirect) between the sponsor, its affiliates, or promoters as one group, and purchasers in the offering as another group in determining whether a particular target business is an appropriate business with which to effectuate 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 24 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 warrants 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. 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.

The following table sets forth the payments to be received by our sponsor and its affiliates from us prior to or in connection with the completion of our initial business combination and the securities issued and to be issued by us to our sponsor or its affiliates.See the section titled “Summary – Sourcing of Potential Initial Business Combination Targets,” “Proposed Business – Sourcing of Potential Initial Business Combination Targets” on page109**, “Management — Conflicts of Interest” on page144, “Management – Executive Officer and Director Compensation” on page139,” “Certain Relationships and Related Party transactions” on page154, “Description of Securities – Private Units,” on page158, “Description of Securities – Working Capital Loan Units,”on page158, “Description of Securities – Founder Shares” on page161, “Description of Securities – $15 Exercise Price Warrants” on page157, and “Description of Securities – Registration Rights Agreement,” and “Risk Factors – Since our sponsor, executive officers and directors will lose their entire investment in us if our initial business combination is not completed (other than with respect to public shares they may acquire during or after this offering), a conflict of interest may arise in determining whether a particular business combination target is appropriate for our initial business combination” on page65 for more information.**

directly in such negotiations; (d) consulting with us with respect to the contents of the materials that may be made available by us to potential targets; (e) devising a plan of evaluating potential targets including their identification and pre-qualification; (f) organizing, arranging and accompanying our management team to meetings regarding the business combination; (g) participating in due diligence, and (h) performing such other investment banking and financial advisory services as we and Imperii Securities LLC may from time to time agree upon in writing. We will pay Imperii Securities LLC a fee for such services (the “Transaction Fee”) upon the consummation of our initial business combination in an amount equal to 1.0% of the consideration paid in connection with the business combination; provided that the Transaction Fee shall not be less than $1,000,000 or greater than $3,000,0000; and further provided that the first $1,000,000 of the Transaction Fee shall be paid with 100,000 shares held by the Sponsor, and the remainder shall be paid by the post-closing company (i) from cash remaining in the trust account after redemptions, if any, or (ii) by the issuance of shares valued at $10 per share.

Because our initial shareholders acquired the founder shares at a nominal price of $0.002, our public shareholders will incur immediate and substantial dilution upon the closing of this offering, assuming no value is ascribed to the warrants included in the units. Further, in the case that additional ordinary shares or equity-linked securities are issued or deemed issued in excess of the amounts sold in this offering and related to or in connection with the closing of the initial business combination, we will effect a share capitalization immediately prior to the consummation of the initial business combination in such amount as to maintain the ownership of the initial shareholders prior to the initial business combination at 20.0% of the issued and outstanding ordinary shares upon the consummation of the initial business combination (not including ordinary shares underlying the warrants, $15 Exercise Price Warrants, private units, Underwriter Units or working capital loan units, if any) (after giving effect to any redemptions of ordinary shares by public shareholders), including the total number of ordinary shares issued, or deemed issued or issuable upon conversion or exercise of any equity-linked securities or warrants issued or deemed issued, by us in connection with or in relation to the consummation of the initial business combination, and excluding any shares or equity- linked securities or warrants exercisable for or convertible into shares issued, or to be issued, to any seller in the initial business combination.**See the section titled “Risk Factors — Risks Relating to our Securities — Our sponsor paid an aggregate of $10,000 to cover certain of our offering costs in exchange for 5,750,000 founder shares, or approximately $0.002 per founder share and, accordingly, you will experience immediate and substantial dilution from the purchase of our ordinary shares.”**Public shareholders will experience additional dilution from the issuance of the private shares (including private shares underlying private units issued upon conversion of working capital loans). Further, upon exercise of the private warrants and the exercise of the $15 Exercise Price Warrants, we will issue an aggregate of 1,137,500 Class A ordinary shares (whether or not the over-allotment option is exercised). Additional shares may be issued upon exercise of any private warrants underlying private units issued upon conversion of working capital loans. The assumed exercise of the $15 Exercise Price Warrants would cause the actual dilution to the public shareholders to be higher, particularly where a cashless exercise is utilized. As a result, the compensation to be paid and securities issued to the sponsor, its affiliates, and promoters, may result in a material dilution of the equity interests of public shareholders.

Investing in our securities involves a high degree of risk. See “Summary – The Offering – Founder Shares,” “Summary –The Offering – Private units and underlying securities,” “Summary –The Offering – $15 Exercise Price Warrants,” “Risk Factors” and “Certain Relationships and Related Party Transactions”. 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.

Of the proceeds we receive from this offering and the sale of the private placement securities described in this prospectus, $200,000,000, or $230,000,000 if the underwriters’ over-allotment option is exercised in full (approximately $10.00 per unit in each case), will be deposited into a trust account in the United States with Odyssey Transfer and Trust Company acting as trustee, after deducting $1,000,000 (plus, if applicable, 0.5% of the gross proceeds from the sale of the over-allotment unit) in underwriting commissions payable upon the closing of this offering and an aggregate of $842,500 (regardless of whether the over-allotment option is exercised) to pay fees and expenses in connection with the closing of this offering and for working capital following the closing of this offering.

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 , 2025.

The date of this prospectus is , 2025