Clearthink 1 Acquisition Corp.

As filed with the U.S. Securities and Exchange Commission on January 26, 2026

Registration No. 333-

**UNITED STATES

SECURITIES AND EXCHANGE COMMISSION****

**Washington, D.C. 20549

FORMS-1**

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ClearThink 1 Acquisition Corp.**

**(Exact name of registrant as specified in its charter)

**William Brock

Chief Executive Officer

ClearThink 1 Acquisition Corp.

150 E. Palmetto Park Road

**Suite 202

Boca Raton, Florida 33432

Tel: (561) 358-3696

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

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 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.

**SUBJECT TO COMPLETION, DATED JANUARY 26, 2026

PRELIMINARY PROSPECTUS

$150,000,000

ClearThink 1 Acquisition Corp.

15,000,000 Units

CLEARTHINK 1 ACQUISITION CORP. is a blank check company incorporated as a Cayman Islands exempted company whose business purpose is to effect a merger, amalgamation, share exchange, asset acquisition, share purchase, reorganization or similar business combination withone 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, or initiated any substantive discussions, directly or indirectly, with any business combination target with respect to an initial business combination with us. Although we are not limited to a particular industry or geographic region for purposes of consummating an initial business combination, we intend to focus on financial services sector in the United States and other developed countries.

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 of a par value US$0.0001 each (a “Class A ordinary share”) and of one right entitling the holder thereof to receive one-tenth of one Class A ordinary share upon the consummation of an initial business combination, as described in more detail in this prospectus. No fractional shares will be issued upon conversion of the rights. As a result, a rights holder must have ten rights to receive one Class A ordinary share at the closing of the initial business combination. The underwriters have a 45-day option from the date of this prospectus to purchase up to 2,250,000 additional units to cover over-allotments, if any.

We will provide our public shareholders with the opportunity to redeem all or a portion of their Class A ordinary shares that were 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 (which interest shall be net of taxes payable), divided by the number of then issued and outstanding public shares, subject to applicable law and 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 the closing of 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. 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.

Our sponsor, ClearThink 1 Sponsor LLC, a Florida limited liability company (which we refer to as our “sponsor” throughout this prospectus), or its affiliates has committed to purchase 350,000 units, or “private units,” at a price of $10.00 per unit in a private placement that will close simultaneously with the closing of this offering. Each private unit will consist of one Class A ordinary share and one right. We refer to the Class A ordinary shares included in the private units throughout this prospectus as the “private shares” and the rights included in the private units as the “private rights.” The private units are identical to the units sold in this offering, subject to certain limited exceptions as described in this prospectus.

Our sponsor paid $25,000 for an aggregate of 5,750,000 Class B ordinary shares of par value US$0.0001 each (a “Class B ordinary share”) (up to 750,000 of which will be surrendered to us for no consideration after the closing of this offering depending on the extent to which the underwriters’ option to purchase additional units (the “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 holder thereof, on a one-for-one basis, subject to adjustment, as described in this prospectus (such shares henceforth referred to as the “founder shares”). The nominal purchase price paid by our sponsor for the founder shares will significantly dilute the implied value of your public shares upon 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 Class A ordinary shares to decline materially.See the section titled “Dilution”on page 80 for more information. See“Risk Factor — Our initial shareholder paid an aggregate of $25,000 or approximately $0.005 per founder share and, accordingly, you will experience immediate and substantial dilution from the purchase of our Class A ordinary shares.” on page 66 and “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 Class A ordinary shares to materially decline.” on page 55.

Because our sponsor acquired the Class B ordinary shares at a nominal price, our public shareholders will incur an immediate and substantial dilution upon the closing of this offering. Further, 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. In the case that additional Class A ordinary shares, or equity-linked securities (as described herein), are issued or deemed issued in excess of the amounts issued in this offering and related to the closing of our initial business combination, the ratio at which the Class B ordinary shares will convert into Class A ordinary shares will be adjusted (unless the holders of a majority of the issued and outstanding Class B ordinary shares agree to waive such anti-dilution adjustment with respect to any such issuance or deemed issuance) so that the number of Class A ordinary shares issuable upon conversion of all Class B ordinary shares will equal, in the aggregate, 25% of the sum of (i) all ordinary shares issued and outstanding upon the completion of this offering (including any Class A ordinary shares issued pursuant to the underwriters’ over-allotment option and excluding the securities underlying the private units issued to the sponsor), plus (ii) all Class A ordinary shares and equity-linked securities issued or deemed issued in connection with the closing of our initial business combination (excluding any shares or equity-linked securities issued, or to be issued, to any seller in the initial business combination and any private units issued to our sponsor or any of its affiliates or to our officers or directors upon conversion of working capital loans) and minus (iii) any redemptions of Class A ordinary shares by public shareholders in connection with an initial business combination; provided that such conversion of founder shares will never occur on a less than one-for-one basis.

Prior to the closing of our initial business combination, only the holder(s) of our Class B ordinary shares will be entitled to vote on (i) the appointment or removal of directors and (ii) continuing the company in a jurisdiction outside the Cayman Islands (including any special resolution required to amend or restate the constitutional documents of the company or to adopt new constitutional documents of the company, in each case, as a result of the company 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, the holder(s) 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.

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 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 (as defined below), or by such earlier liquidation date as our board of directors may approve, the founder shares, private shares and private rights will be 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. See “Principal Shareholders” for further information regarding the beneficial ownership of our company by management and our sponsor. 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. Additionally, commencing on the date on which our securities are listed on Nasdaq, we will pay our sponsor an amount equal to $15,000 per month for office space, secretarial and administrative services made available to us, as described elsewhere in this prospectus.Upon consummation of this offering, we will repay up to $500,000 in loans made to us by our sponsor to cover offering-related and organizational expenses. In the event that following this offering we obtain working capital loans from our sponsor to finance transaction costs related to our initial business combination, up to $1,500,000 of such loans may be convertible into units of the post-business combination entity at a price of $10.00 per unit at the option of our sponsor. Additionally, our sponsor, our officers and directors or their affiliates may be paid finder’s fees, advisory fees, consulting fees or success fees in order to effectuate the completion of our initial business combination. Additionally, following consummation of a business combination, members of our management team will be entitled to reimbursement for any out-of-pocket expenses related to identifying, investigating and completing an 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, or our promoters on one hand, and purchasers in this offering on the other. See “Summary — Sponsor Information”, “Summary — The Offering — Founder Shares”, “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

Our sponsor, its affiliates, or promoters and members of our management team will directly or indirectly own ordinary shares, or other instruments linked to our private units, 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. 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. We are not prohibited from pursuing an initial business combination with a company that is affiliated with our sponsor, officers or directors, or completing the business combination through a joint venture or other form of shared ownership with our sponsor, officers or directors. In the event we seek to complete our initial business combination with a target that is affiliated with our sponsor, officers or directors, we, or a committee of independent directors, would obtain an opinion from an independent firm that commonly renders valuation opinions, independent accounting firm or independent investment banking firm that our initial business combination is fair to our company from a financial point of view. We are not required to obtain such an opinion in any other context.

There may be potential material conflicts of interest between the sponsor, its affiliates, or promoters and the purchasers in this offering. Our sponsor, along with its affiliates, promoters, officers, and directors, currently participate, and may in the future participate, in the formation or sponsorship of other special purpose acquisition companies (“SPACs”) similar to ours, or engage in other business or investment ventures during our pursuit of an initial business combination. Despite these activities, our officers and directors will maintain their existing fiduciary duty to us, and we will retain priority over any subsequent SPACs or ventures they may join.

For a description of risks associated with compensation and material conflicts of interests of our sponsor, its affiliates, or promoters, see*“Our Business Combination Process,” “Principal Shareholders,” “Risk Factors — Risks Relating to our Management Team,” “Risk Factors — Risks Relating to Our Search for, and Consummation of or Inability to Consummate, a Business Combination,” “Risk Factors — Risks Related to Our Securities,”, “Management — Officers and Directors*,” “Management — Conflicts of Interest,” “The Offering — Conflicts of Interest,” “Certain Relationships and Related Party Transactions,” and “Proposed Business”for further information.

The following table illustrates our net tangible book value (“net tangible book value” or “NTBV”) per share at the specified redemption levels:

See the Section entitled “Dilution” of this prospectus on page 80 for additional information.

Of the proceeds we receive from this offering and the sale of the private units described in this prospectus, $150,000,000, or $172,500,000 if the underwriters’ over-allotment option is exercised in full ($10.00 per unit in either case), will be deposited into a trust account located in the United States with Equiniti Trust Company, LLC, acting as trustee and held as cash (including in interest bearing demand deposits) or invested only in U.S. government treasury obligations 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 of 1940, as amended, which invest only in direct U.S. government treasury obligations. Except with respect to interest earned on the funds held in the trust account that may be released to us to pay our income and franchise taxes, if any, the proceeds from this offering and the sale of the private units will not be released from the trust account until the earliest of (i) the completion of our initial business combination, (ii) the redemption of our public shares if we are unable to complete our initial business combination within the completion window, subject to applicable law, or (iii) the redemption of our public shares properly submitted in connection with a shareholder vote to amend or restate our amended and restated memorandum and articles of association (A) to modify the substance or timing of our obligation to allow redemption in connection with the closing of our initial business combination or to redeem 100% of our public shares if we have not consummated an initial business combination within the completion window or (B) with respect to any other material provisions relating to (x) the rights of holders of our Class A ordinary shares or (y) pre-initial business combination activity. The proceeds deposited in the trust account could become subject to the claims of our creditors, if any, which could have priority over the claims of our public shareholders.

We have until the date that is 21 months from the closing of this offering (or 24 months in the event that a definitive business combination agreement has been publicly announced) or until such earlier liquidation date as our board of directors may approve (the “completion window”) to consummate our initial business combination. While we currently do not plan to extend the time to complete a business combination beyond 21 months (or 24 months in the event that a definitive business combination agreement has been publicly announced), if we anticipate that we may be unable to consummate our initial business combination within such 21-month period (or 24 months in the event that a definitive business combination agreement has been publicly announced), we may 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, provided we deposit an additional $0.033 per share, or such lesser amount as shall be acceptable to the non-redeeming public holders, for each month in the trust account. If we seek shareholder approval for an extension, and the related amendments to our amended and restated memorandum and articles of association are approved by the shareholders, public holders of Class A ordinary 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 (which interest shall be net of taxes payable), divided by the number of then issued and outstanding public shares, subject to applicable law and certain conditions as further described herein.

Our initial shareholder will lose their entire investment in us if our initial business combination is not completed within 21 months from the closing of this offering (or 24 months in the event that a definitive business combination agreement has been publicly announced) unless we extend the amount of time we have to consummate an initial business combination by obtaining shareholder approval to amend our amended and restated memorandum and articles of association. While we do not currently intend to seek such shareholder approval, we may elect to do so in the future. There is no limit on the number of extensions that we may seek. If we do not or are unable to extend the time period to consummate our initial business combination, our sponsor’s investment in our founder shares and our private units will be worthless.

If we are unable to complete our initial business combination within the completion window (including any extensions), 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 (which interest shall be net of taxes payable and less up to $250,000 of interest income to pay liquidation and dissolution expenses), divided by the number of then issued and outstanding public shares, which redemption will constitute full and complete payment for the public shares and completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidation or other distributions, if any), subject to our obligations under Cayman Islands law to provide for claims of creditors and subject to the other requirements of applicable law. The redemption rights will also include the requirement that any beneficial owner on whose behalf a redemption right is being exercised must identify itself in order to validly redeem its shares.

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 The Nasdaq Global Market, or Nasdaq, under the symbol “CTAAU” on or promptly after the date of this prospectus. It is a condition to closing of this offering that the units be approved for listing by Nasdaq. We cannot guarantee that our securities will be approved for listing on the Nasdaq. 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 D. Boral Capital LLC (“D. Boral”), the representative of the underwriters of this offering, 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 the Nasdaq under the symbols “CTAA” and “CTAAR”, 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 36 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.

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.

Sole Book Running Manager

D. Boral Capital LLC

, 2026

TABLE OF CONTENTS

We are responsible for the information contained in this prospectus. We have not authorized anyone to provide you with different information, and we take no responsibility for any other information others may give to you. 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.

TRADEMARKS

This prospectus contains references to trademarks and service marks belonging to other entities. Solely for convenience, trademarks and trade names referred to in this prospectus may appear without the® or TM symbols, but such references are not intended to indicate, in any way, that the applicable licensor will not assert, to the fullest extent under applicable law, its rights to these trademarks and trade names. We do not intend our use or display of other companies’ trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

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