[Form 4] Centessa Pharmaceuticals plc American Insider Trading Activity

Rhea-AI Filing Summary

Centessa Pharmaceuticals CEO Saurabh Saha executed significant stock transactions on June 20, 2025. The transactions involved:

• Exercised 55,000 stock options at $3.85 per share
• Subsequently sold 55,000 ordinary shares at weighted average price of $12.63 per share
• Sales were executed under a pre-established Rule 10b5-1 trading plan from May 16, 2024

Post-transactions, Saha holds 221,017 ordinary shares directly and 38,000 shares indirectly through a trust. He retains 205,000 stock options exercisable until February 2033. The options vest monthly at 1/48th rate starting March 2023. This transaction resulted in an approximate gross profit of $483,000 before taxes and fees.

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

SAHA SAURABH

(Last) (First) (Middle)

C/O CENTESSA PHARMACEUTICALS PLC

3RD FL., 1 ASHLEY RD, ALTRINCHAM

(Street)

CHESHIRE X0 WA14 2DT

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Centessa Pharmaceuticals plc [ CNTA ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
06/20/2025

4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Ordinary Shares(1)	06/20/2025		M		55,000	A	$3.85	276,017	D
Ordinary Shares(1)	06/20/2025		S(2)		55,000	D	$12.6332(3)	221,017	D
Ordinary Shares(1)								38,000	I	By trust(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Share Option (right to buy)	$3.85	06/20/2025		M			55,000	(5)	02/01/2033	Ordinary Shares(1)	55,000	$0	205,000	D

Explanation of Responses:

1. The Ordinary Shares may be represented by American Depositary Shares, each of which currently represents one Ordinary Share.

2. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 16, 2024.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $12.50 to $12.80, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

4. These shares are held directly in a trust, for which the Reporting Person and his spouse serve as trustees.

5. 1/48th of the shares subject to such option shall vest and become exercisable in equal monthly installments with the first installment vesting on March 1, 2023.

Remarks:

	/s/ Gregory Weinhoff, attorney-in-fact	06/20/2025
	** 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 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.

FAQ

How many CNTA shares did CEO Saurabh Saha sell on June 20, 2025?

CEO Saurabh Saha sold 55,000 ordinary shares of CNTA on June 20, 2025 at a weighted average price of $12.6332 per share. The shares were sold in multiple transactions at prices ranging from $12.50 to $12.80.

What was the total value of CNTA shares sold by CEO Saurabh Saha?

Based on the weighted average sale price of $12.6332 per share for 55,000 shares, the total value of the transaction was approximately $694,826.

How many CNTA shares does CEO Saurabh Saha still own after the June 2025 transaction?

After the transaction, CEO Saurabh Saha owns 221,017 shares directly and 38,000 shares indirectly through a trust, for a total of 259,017 shares. He also holds 205,000 stock options.

Was CNTA CEO Saha's stock sale part of a pre-planned trading arrangement?

Yes, the sales were executed pursuant to a Rule 10b5-1 trading plan that was adopted by Saurabh Saha on May 16, 2024, approximately 13 months before the transaction.

What is the exercise price of CNTA CEO Saha's stock options?

The stock options have an exercise price of $3.85 per share and expire on February 1, 2033. The options vest in equal monthly installments, with 1/48th of the shares vesting monthly starting March 1, 2023.