[Form 4] Centessa Pharmaceuticals plc American Insider Trading Activity

Rhea-AI Filing Summary

Centessa (NASDAQ:CNTA) filed a Form 4 showing that President, Orexin Program Mario Alberto Accardi exercised options for 15,000 ordinary shares at $3.85 and immediately sold the same 15,000 shares at $14.00 on 06/24/2025 under a Rule 10b5-1 plan.

The transaction generated roughly $210 k in gross proceeds and reduced his direct holdings by 6.5% to 216,485 shares; he still holds 15,300 vested options. Because the sale exceeds 5% of his prior stake, it meets materiality thresholds for insider activity that investors track for sentiment shifts.

Positive

• None.

Negative

• Insider sale: Accardi disposed of 15,000 shares (~6.5% of his stake) at $14, generating ~$210 k and modestly reducing insider ownership.

Insights

Insider-Trading Analyst

TL;DR: 6.5% insider sale via cashless exercise; watch but not alarming given residual stake.

Scale: 15,000 shares is modest in dollar terms (~$210 k) yet represents >6% of Accardi’s prior position, clearing the SEC materiality bar. Structure: The sale paired with option exercise suggests a cash-neutral liquidity event, typical for covering costs/taxes rather than outright exit. Plan: Executed under a pre-established 10b5-1 plan, which reduces informational asymmetry risk but doesn’t eliminate signalling value. Residual Alignment: Post-sale holding of 216,485 shares and 15,300 options indicates continued economic exposure, tempering bearish interpretations. Takeaway: Worth monitoring for follow-on sales; alone it points to personal liquidity rather than a fundamental red flag.

Portfolio Manager

TL;DR: Small dollar value, but first notable insider trim since 2024—keep an eye on future pattern.

The $14 exit price versus a $3.85 strike locks in a healthy spread, hinting management confidence when options were awarded but also willingness to monetize after recent price strength. While proceeds are under $1 m, the >5% stake reduction could influence sentiment for a micro-cap biotech where insider alignment is closely watched. The 10b5-1 shield reduces headline risk, yet repeated disposals of similar magnitude could pressure shares by signalling limited near-term catalysts. For now, I view the event as neutral-to-slightly-negative; position sizing remains large enough to keep management interests aligned, but I would track subsequent filings for trend confirmation.

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^*

Accardi Mario Alberto

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President, Orexin Program

3. Date of Earliest Transaction (Month/Day/Year)
06/24/2025

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)	06/24/2025		M		15,000	A	$3.85	231,485	D
Ordinary Shares(1)	06/24/2025		S(2)		15,000	D	$14	216,485	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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Share Option (right to buy)	$3.85	06/24/2025		M			15,000	(3)	02/01/2033	Ordinary Shares(1)	15,000	$0	15,300	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 February 14, 2025.

3. 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	06/25/2025
	** 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 Mario A. Accardi sell on 06/24/2025?

He sold 15,000 ordinary shares (or equivalent ADS) on 06/24/2025.

At what price were Centessa shares sold in the latest Form 4?

Shares were sold at $14.00 per share under a Rule 10b5-1 trading plan.

What was the exercise price of the options exercised by Accardi?

The options were exercised at $3.85 per share.

How many CNTA shares does Accardi own after the reported transaction?

Following the sale, he owns 216,485 ordinary shares directly and 15,300 vested options.

Did the transaction occur under a 10b5-1 trading plan?

Yes. The filing states the sales were executed pursuant to a Rule 10b5-1 plan adopted on 02/14/2025.