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

Yes. The filing states that the sales were carried out under a Rule 10b5-1 trading plan adopted on November 12, 2025. Such pre-arranged plans automate trading and can indicate the timing was scheduled rather than based on new information.

Centessa (NASDAQ: CNTA) CPO exercises options, sells 120K shares

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

4/A

Rhea-AI Filing Summary

Centessa Pharmaceuticals plc Chief People Officer Karen M. Anderson reported an exercise-and-sell transaction in the company’s Ordinary Shares. She exercised share options covering 109,398 Ordinary Shares at exercise prices of $4.01 and $3.85 per share, converting them into Ordinary Shares.

On the same date, she sold a total of 120,029 Ordinary Shares in open-market transactions at weighted average prices of $26.1505 and $27.1328 per share, pursuant to a pre-arranged Rule 10b5-1 trading plan adopted on November 12, 2025. Following these transactions, she directly holds 62,085 Ordinary Shares.

Insider Trade Summary 10b5-1

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

Net Sell 6 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)	94,224	$0.00	--
Exercise	Share Option (right to buy)	15,174	$0.00	--
Exercise	Ordinary Shares	94,224	$4.01	$378K
Exercise	Ordinary Shares	15,174	$3.85	$58K
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) — 149,811 shares (Direct); Ordinary Shares — 166,940 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. 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.

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Form 4 Insider Transactions: What Each Field Means →

03/16/2026 - 06:09 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)
03/13/2026

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

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

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		94,224	A	$4.01	166,940	D
Ordinary Shares⁽¹⁾	03/13/2026		M		15,174	A	$3.85	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			94,224	⁽⁵⁾	12/01/2032	Ordinary Shares⁽¹⁾	94,224	$0	149,811	D
Share Option (right to buy)	$3.85	03/13/2026		M			15,174	⁽⁶⁾	02/01/2033	Ordinary Shares⁽¹⁾	15,174	$0	28,336	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.

6. 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:

This Form 4/A amends and restates the Form 4 filed on March 13, 2026 to correct the reporting of stock option exercises. The exercises were previously reported as originating from a single option grant but were exercised from two separate option grants with different exercise prices. This amendment reports the exercises from each grant at the applicable exercise prices. Except for the corrected reporting of the option exercises, the transactions and amounts previously reported remain unchanged.

	/s/ Raphael Deferiere, attorney-in-fact	03/16/2026
	** 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 insider transactions did Centessa (CNTA) report for Karen M. Anderson?

Karen M. Anderson exercised options for 109,398 Ordinary Shares and sold 120,029 Ordinary Shares in open-market trades. These transactions occurred on March 13, 2026 and were reported on an amended Form 4/A for Centessa Pharmaceuticals.

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

She sold 120,029 Ordinary Shares in two weighted-average price groups: 107,961 shares at about $26.1505 and 12,068 shares at about $27.1328 per share. Both price figures reflect ranges of individual trade prices disclosed in the filing footnotes.

What options did Karen M. Anderson exercise in the latest Centessa (CNTA) Form 4/A?

She exercised two share option grants covering 94,224 Ordinary Shares at an exercise price of $4.01 and 15,174 Ordinary Shares at $3.85. These exercises converted her derivative positions into Ordinary Shares before the reported open-market sales.

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

After exercising options and selling shares, Karen M. Anderson directly holds 62,085 Ordinary Shares. This post-transaction holding reflects her remaining equity position reported in the Form 4/A following the March 13, 2026 trades.

What do the weighted-average prices mean in Karen M. Anderson’s Centessa (CNTA) trades?

The reported prices of $26.1505 and $27.1328 are weighted averages across multiple trades within specified price ranges. The filing notes individual trades occurred between $25.75 and $27.455, and detailed trade-level pricing is available upon request.