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

Yes. The Form 4 states the sales were effected pursuant to a Rule 10b5-1 trading plan adopted on November 12, 2025. Such plans pre-schedule trades, indicating these transactions were arranged in advance rather than timed in response to near-term company developments.

Centessa (NASDAQ: CNTA) CPO exercises options and sells 74,811 shares

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

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. On March 16–17, 2026, she exercised options for 74,811 Ordinary Shares at an exercise price of $4.01 per share and received the same number of shares.

She then sold 64,768 shares at a weighted average price of $28.2079 on March 16, 2026 and 10,043 shares at a weighted average price of $28.1002 on March 17, 2026, totaling 74,811 shares sold. After these transactions, she directly owns 62,085 Ordinary Shares. The sales were made under a pre-arranged Rule 10b5-1 trading plan adopted on November 12, 2025.

Insider Trade Summary 10b5-1

Net Seller: 74,811 shares ($2,109,180)

Net Sell 6 txns

Insider Anderson Karen M.

Role Chief People Officer

Sold 74,811 shs ($2.11M)

Type	Security	Shares	Price	Value
Exercise	Share Option (right to buy)	10,043	$0.00	--
Exercise	Ordinary Shares	10,043	$4.01	$40K
Sale	Ordinary Shares	10,043	$28.1002	$282K
Exercise	Share Option (right to buy)	64,768	$0.00	--
Exercise	Ordinary Shares	64,768	$4.01	$260K
Sale	Ordinary Shares	64,768	$28.2079	$1.83M

Holdings After Transaction: Share Option (right to buy) — 75,000 shares (Direct); Ordinary Shares — 72,128 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 $27.99 to $28.41, 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 $27.99 to $28.21, 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 →

03/18/2026 - 06:43 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)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/16/2026

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

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

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

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⁾	03/16/2026		M		64,768	A	$4.01	126,853	D
Ordinary Shares⁽¹⁾	03/16/2026		S⁽²⁾		64,768	D	$28.2079⁽³⁾	62,085	D
Ordinary Shares⁽¹⁾	03/17/2026		M		10,043	A	$4.01	72,128	D
Ordinary Shares⁽¹⁾	03/17/2026		S⁽²⁾		10,043	D	$28.1002⁽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	03/16/2026		M			64,768	⁽⁵⁾	12/01/2032	Ordinary Shares⁽¹⁾	64,768	$0	85,043	D
Share Option (right to buy)	$4.01	03/17/2026		M			10,043	⁽⁵⁾	12/01/2032	Ordinary Shares⁽¹⁾	10,043	$0	75,000	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 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 $27.99 to $28.41, 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 $27.99 to $28.21, 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	03/18/2026
	** 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.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What did Centessa (CNTA) Chief People Officer Karen Anderson report in this Form 4?

She reported exercising stock options for 74,811 Centessa Ordinary Shares at an exercise price of $4.01 per share, then selling all 74,811 shares in open-market transactions, and finishing with direct ownership of 62,085 Ordinary Shares after the transactions.

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

She sold a total of 74,811 Ordinary Shares. On March 16, 2026 she sold 64,768 shares at a weighted average price of $28.2079, and on March 17, 2026 she sold 10,043 shares at a weighted average price of $28.1002.

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

Following the option exercises and subsequent sales, she directly owns 62,085 Centessa Ordinary Shares. The Form 4 indicates this post-transaction balance in the total shares following transaction column for the final reported sale entry on March 17, 2026.

What type of securities did Karen Anderson exercise and sell in Centessa (CNTA)?

She exercised “Share Option (right to buy)” derivative securities into 74,811 Centessa Ordinary Shares at an exercise price of $4.01. All resulting Ordinary Shares from these exercises were then sold in open-market transactions at weighted average prices around $28.20 per share.

Does Karen Anderson have any remaining Centessa (CNTA) options from this grant?

The filing shows derivative transactions covering 74,811 option shares with no remaining derivative positions listed in the derivative summary. This indicates the reported options from this grant were fully exercised in these transactions, with the resulting shares subsequently sold.