# EDGAR Filing Document

**Accession Number:** 0002114325
**File Stem:** 0001493152-26-009172
**Filing Date:** 2026-3
**Character Count:** 6415
**Document Hash:** f8375dfea6417efd00973672485e0077
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001493152-26-009172.hdr.sgml**: 20260306

**ACCESSION NUMBER**: 0001493152-26-009172

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260225

**FILED AS OF DATE**: 20260306

**DATE AS OF CHANGE**: 20260306

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Brock William
- **CENTRAL INDEX KEY:** 0002114325

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-43139
- **FILM NUMBER:** 26732002

**MAIL ADDRESS:**
- **STREET 1:** 370 PARK AVE.
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Clearthink 1 Acquisition Corp.
- **CENTRAL INDEX KEY:** 0002094073
- **STANDARD INDUSTRIAL CLASSIFICATION:** BLANK CHECKS [6770]
- **ORGANIZATION NAME:** 05 Real Estate & Construction
- **EIN:** 000000000
- **STATE OF INCORPORATION:** E9
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 851 BROKEN SOUND PARKWAY NW
- **STREET 2:** SUITE 280
- **CITY:** BOCA RATON
- **STATE:** FL
- **ZIP:** 33487
- **BUSINESS PHONE:** 561-807-9010

**MAIL ADDRESS:**
- **STREET 1:** 851 BROKEN SOUND PARKWAY NW
- **STREET 2:** SUITE 280
- **CITY:** BOCA RATON
- **STATE:** FL
- **ZIP:** 33487

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

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Brock William<br><sub>(Last) (First) (Middle)</sub><br>C/O CLEARTHINK 1 ACQUISITION CORP.<br>150 E. PALMETTO PARK ROAD, SUITE 202<br><sub>(Street)</sub><br>BOCA RATON,, FL 33432<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>Clearthink 1 Acquisition Corp. [ CTAA ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2026-02-25 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director   [ ] 10% Owner<br>[X] Officer (give title below)   [ ] Other (specify below)<br>_CEO and President_ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Class A Ordinary Shares | 315000<sup>(1)</sup> | I | By ClearThink 1 Sponsor LLC<sup>(2)</sup> |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| Class B Ordinary Shares<sup>(2)(3)</sup> | <sup>(3)</sup> | <sup>(3)</sup> | Class A Ordinary Shares | 4791667<sup>(3)(4)</sup> | <sup>(3)</sup> | I | By ClearThink 1 Sponsor LLC<sup>(2)</sup> |
| Rights | <sup>(5)</sup> | <sup>(5)</sup> | Class A Ordinary Shares | 63000<sup>(5)</sup> | <sup>(5)</sup> | I | By ClearThink 1 Sponsor LLC<sup>(2)</sup> |

---

### Footnotes:

(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.

**Signature:** /s/ William Brock  
**Date:** 2026-03-06

### Remarks:

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 4 (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.**