SEC FORM 3

SEC FORM 3 SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Brock William

(Last)

(First)

(Middle)

C/O CLEARTHINK 1 ACQUISITION CORP.

150 E. PALMETTO PARK ROAD, SUITE 202

(Street)

BOCA RATON,

33432

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
02/25/2026

3. Issuer Name and Ticker or Trading Symbol
Clearthink 1 Acquisition Corp. [ CTAA ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	CEO and President

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Class A Ordinary Shares	315,000⁽¹⁾	I	By ClearThink 1 Sponsor LLC⁽²⁾

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Class B Ordinary Shares⁽²⁾⁽³⁾	⁽³⁾	⁽³⁾	Class A Ordinary Shares	4,791,667⁽³⁾⁽⁴⁾	⁽³⁾	I	By ClearThink 1 Sponsor LLC⁽²⁾
Rights	⁽⁵⁾	⁽⁵⁾	Class A Ordinary Shares	63,000⁽⁵⁾	⁽⁵⁾	I	By ClearThink 1 Sponsor LLC⁽²⁾

Explanation of Responses:

1. Represents Class A ordinary shares underlying the private placement units (the "Private Units") purchased concurrently with the initial public offering of the Issuer. The number of Class A ordinary shares does not include the rights entitling the holder to receive one-fifth of one Class A ordinary share upon the consummation of a business combination, which comprise a part of the Private Units of the Issuer purchased by ClearThink 1 Sponsor LLC (the "Sponsor") concurrently with the consummation of the Issuer's initial public offering.

2. The Sponsor is the record holder of the shares reported herein. ClearThink 1 Sponsor Manager LLC, the managers of which are the Reporting Person, the Issuer's Chief Executive Officer, and Ari Brown, a Managing Director at ClearThink Capital LLC, is the sole managing members of the Sponsor. Mr. Brock and Mr. Brown have sole voting and investment discretion with respect to the ordinary shares held of record by the Sponsor.

3. As described in the Issuer's Registration Statement on Form S-1, as amended (File No. 333-292967) under the heading "Description of Securities - Ordinary Shares", the Class B Ordinary Shares will automatically convert into Class A ordinary shares at the time of the Issuer's initial business combination or earlier at the option if the holder on a one-for-one basis, subject to certain adjustments described therein and have no expiration date.

4. Includes up to 625,000 founder shares that will be forfeited depending on the extent to which the underwriters' over-allotment option is exercised.

5. Represents 315,000 rights underlying the Private Units. Each right entitles the holder to receive one-fifth of one Class A ordinary share upon the consummation of the Issuer's initial business combination.

	/s/ William Brock	03/06/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

New insider Brock William claimed ownership of 315,000 units of Class A Ordinary Shares (SEC Form 3)