[Form 4] Centessa Pharmaceuticals plc American Insider Trading Activity

Rhea-AI Filing Summary

On 07/21/2025, Centessa Pharmaceuticals plc (CNTA) Chief Executive Officer and Director Dr. Saurabh Saha filed a Form 4 reporting an option exercise and same-day sale of company stock.

• Option exercise: 55,000 share options were exercised at $3.85, converting into ordinary shares.
• Share sale: The identical 55,000 shares were sold under a Rule 10b5-1 trading plan at a volume-weighted average price of $15.92 (price range $15.80-$16.05).
• Post-transaction holdings: Dr. Saha now owns 221,017 ordinary shares directly and 38,000 shares indirectly through a family trust, plus 150,000 remaining options that vest monthly and expire 02/01/2033.

The filing contains no operational or financial performance data; it solely documents this insider transaction.

Positive

• CEO retains 221,017 direct shares and 38,000 trust shares, signalling ongoing equity alignment.
• Transaction executed under a pre-arranged Rule 10b5-1 plan, reducing potential governance concerns.

Negative

• 55,000 shares sold at $15.92 average price, representing a cash realisation by the CEO.
• Exercise-and-sale reduces immediate insider ownership growth, potentially perceived as mild negative sentiment.

Insights

Financial Analyst

TL;DR: CEO exercised options at $3.85 and sold 55k shares at $15.92; retains 221k shares. Neutral liquidity event.

The exercise was deep in-the-money, realising a spread of roughly $12 per share. Because the sale matched the exercise quantity, the CEO’s direct stake stayed large at 221,017 shares, and he still holds 150,000 unexercised options. The trade was executed under a 10b5-1 plan, reducing the chance of information asymmetry. No change to fundamentals is indicated, so the market impact is likely modest.

Corporate Governance Expert

TL;DR: Rule 10b5-1 plan mitigates governance risk; insider still aligned via sizeable equity.

Structured trading plans are viewed favourably by governance watchdogs because they pre-schedule insider sales. Dr. Saha’s continuing direct and indirect ownership (≈259k shares combined) plus long-dated options maintains alignment with shareholders. The sale does not trigger control-related thresholds and no other insiders are implicated, so the filing is not materially negative.

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).

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)
07/21/2025

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)	07/21/2025		M		55,000	A	$3.85	276,017	D
Ordinary Shares(1)	07/21/2025		S(2)		55,000	D	$15.92(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	07/21/2025		M			55,000	(5)	02/01/2033	Ordinary Shares(1)	55,000	$0	150,000	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 $15.80 to $16.05, 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/ Richard Menziuso, attorney-in-fact	07/21/2025
	** 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 Centessa (CNTA) shares did CEO Saurabh Saha sell on 21-Jul-2025?

He sold 55,000 ordinary shares.

What price did the CEO receive for the CNTA shares sold?

The volume-weighted average sale price was $15.92, with individual trades between $15.80 and $16.05.

How many CNTA shares does Dr. Saha own after the transaction?

He owns 221,017 shares directly and 38,000 shares indirectly via a trust (total ≈259,017 shares).

Was the sale conducted under a Rule 10b5-1 trading plan?

Yes. The Form 4 states the sales were made under a Rule 10b5-1 plan adopted 16-May-2024.

At what price were the options exercised?

The options were exercised at an exercise price of $3.85 per share.

How many unexercised options does the CEO still hold?

Dr. Saha retains 150,000 share options that vest monthly and expire on 01-Feb-2033.