Were Karen M. Anderson’s Centessa (CNTA) share sales under a Rule 10b5-1 plan?

Yes. The Form 4 footnotes state that the reported sales were effected pursuant to a Rule 10b5-1 trading plan adopted by Karen M. Anderson on November 12, 2025, indicating the trades were pre-arranged under that plan.

Centessa (CNTA) CPO exercises 109,398 options and sells 120,029 shares

Filing Impact

(Very High)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Centessa Pharmaceuticals plc Chief People Officer Karen M. Anderson exercised stock options and sold shares in a planned transaction. She exercised options for 109,398 Ordinary Shares at an exercise price of $4.01 per share and received the same number of Ordinary Shares.

On the same date, she sold 107,961 Ordinary Shares at a weighted average price of $26.1505 and 12,068 Ordinary Shares at a weighted average price of $27.1328, in multiple trades within stated price ranges. These sales were made under a Rule 10b5-1 trading plan adopted on November 12, 2025.

After these transactions, Anderson directly holds 62,085 Ordinary Shares. The exercised option, originally granted with vesting beginning on December 1, 2023, is now fully exercised, and no remaining derivative position from this option is shown in this filing.

Insider Trade Summary 10b5-1

Net Seller: 120,029 shares ($3,150,673)

Net Sell 4 txns

Insider Anderson Karen M.

Role Chief People Officer

Sold 120,029 shs ($3.15M)

Type	Security	Shares	Price	Value
Exercise	Share Option (right to buy)	109,398	$0.00	--
Exercise	Ordinary Shares	109,398	$4.01	$439K
Sale	Ordinary Shares	107,961	$26.1505	$2.82M
Sale	Ordinary Shares	12,068	$27.1328	$327K

Holdings After Transaction: Share Option (right to buy) — 134,637 shares (Direct); Ordinary Shares — 182,114 shares (Direct)

Footnotes (1)

The Ordinary Shares may be represented by American Depositary Shares, each of which currently represents one Ordinary Share. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 12, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.75 to $26.705, 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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $26.805 to $27.455, 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. 25% of the shares subject to such option shall vest and become exercisable on December 1, 2023 and the remaining 75% of the shares subject to such option shall vest and become exercisable in 36 monthly installments on the first day of each month thereafter.

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Form 4 Insider Transactions: What Each Field Means →

03/13/2026 - 06:23 PM

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).

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^*

Anderson Karen M.

(Last)

(First)

(Middle)

C/O CENTESSA PHARMACEUTICALS PLC

3RD FL., 1 ASHLEY RD, ALTRINCHAM

(Street)

CHESHIRE

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)

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

3. Date of Earliest Transaction (Month/Day/Year)
03/13/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Ordinary Shares⁽¹⁾	03/13/2026		M		109,398	A	$4.01	182,114	D
Ordinary Shares⁽¹⁾	03/13/2026		S⁽²⁾		107,961	D	$26.1505⁽³⁾	74,153	D
Ordinary Shares⁽¹⁾	03/13/2026		S⁽²⁾		12,068	D	$27.1328⁽⁴⁾	62,085	D

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Share Option (right to buy)	$4.01	03/13/2026		M			109,398	⁽⁵⁾	12/01/2032	Ordinary Shares⁽¹⁾	109,398	$0	134,637	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 November 12, 2025.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.75 to $26.705, 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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $26.805 to $27.455, 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.

5. 25% of the shares subject to such option shall vest and become exercisable on December 1, 2023 and the remaining 75% of the shares subject to such option shall vest and become exercisable in 36 monthly installments on the first day of each month thereafter.

Remarks:

	/s/ Raphael Deferiere, attorney-in-fact	03/13/2026
	** 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 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.

Source: View Original Filing on SEC EDGAR

FAQ

What did Centessa (CNTA) executive Karen M. Anderson do in this Form 4?

Karen M. Anderson exercised stock options and sold shares of Centessa. She converted options into 109,398 Ordinary Shares, then sold 120,029 Ordinary Shares in open-market transactions, ending with 62,085 shares held directly afterward.

How many Centessa (CNTA) options did Karen M. Anderson exercise and at what price?

She exercised options covering 109,398 Ordinary Shares at an exercise price of $4.01 per share. This converted her derivative position into an equivalent number of Ordinary Shares before subsequent open-market sales disclosed in the same Form 4 filing.

How many Centessa (CNTA) shares did Karen M. Anderson sell and at what prices?

She sold 107,961 Ordinary Shares at a weighted average price of $26.1505 and 12,068 shares at a weighted average price of $27.1328, in multiple transactions within specified price ranges during the reported trading day.

How many Centessa (CNTA) shares does Karen M. Anderson hold after these transactions?

Following the reported option exercise and share sales, Karen M. Anderson directly holds 62,085 Ordinary Shares. This figure reflects her position after completing all transactions described in the Form 4 for the stated transaction date.

What is the vesting schedule of the Centessa (CNTA) option exercised by Karen M. Anderson?

The option provided that 25% of the shares vested and became exercisable on December 1, 2023. The remaining 75% vested in 36 equal monthly installments on the first day of each month thereafter, before being fully exercised as reported.