Centessa Pharmaceuticals (CNTA) holders Adage, Atchinson, Gross report 0% stake

Rhea-AI Filing Summary

Centessa Pharmaceuticals plc received an updated Schedule 13G/A from Adage Capital Management, L.P., Robert Atchinson, and Phillip Gross reporting that they no longer beneficially own any ordinary shares or related American Depositary Shares of the company. Each reporting person lists 0 shares beneficially owned and a 0.0% ownership stake, with no sole or shared voting or dispositive power. The amendment confirms that their holdings have fallen to five percent or less of the class.

Key Figures

Beneficial ownership: 0.00 shares Ownership percentage: 0.0% Nominal value per share: 0.002 GBP per share +1 more

4 metrics

Beneficial ownership 0.00 shares Row 9 of the cover page for each reporting person

Ownership percentage 0.0% Percent of class reported under Item 4(b)

Nominal value per share 0.002 GBP per share Ordinary shares of Centessa Pharmaceuticals plc

CUSIP for ADSs 152309100 Assigned to American Depositary Shares representing ordinary shares

Key Terms

beneficially owned, sole voting power, dispositive power, American Depositary Shares, +1 more

5 terms

beneficially owned financial

"Amount beneficially owned: The information required by Item 4(a)..."

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole voting power financial

"5 | Sole Voting Power 0.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

dispositive power financial

"7 | Sole Dispositive Power 0.00 8 | Shared Dispositive Power 0.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

American Depositary Shares financial

"with respect to the American Depositary Shares, each representing one ordinary share"

American depositary shares (ADSs) are a way for investors in the United States to buy shares of foreign companies without dealing with international markets directly. They represent ownership in a foreign company's stock and are traded on U.S. stock exchanges, making it easier for American investors to buy, sell, and own parts of companies from around the world.

Ownership of 5 percent or less of a class financial

"Item 5. | Ownership of 5 Percent or Less of a Class."

FAQ

What does Centessa Pharmaceuticals (CNTA) disclose about Adage Capital's current ownership?

Adage Capital Management and its principals report 0 shares of Centessa Pharmaceuticals beneficially owned, representing 0.0% of the ordinary share class, indicating they no longer have a reportable ownership position.

Which investors are named in the Centessa (CNTA) Schedule 13G/A amendment?

The amendment lists Adage Capital Management, L.P., along with individuals Robert Atchinson and Phillip Gross, as the reporting persons with respect to prior holdings of Centessa ordinary shares underlying ADSs.

What class of securities is covered in this Centessa (CNTA) Schedule 13G/A?

The filing covers ordinary shares of Centessa Pharmaceuticals with a nominal value of 0.002 GBP per share, including shares underlying American Depositary Shares previously quoted under CUSIP 152309100.

What voting and dispositive power do the reporting persons have over Centessa (CNTA) shares?

Each reporting person states 0.00 sole voting power, 0.00 shared voting power, 0.00 sole dispositive power, and 0.00 shared dispositive power, indicating no current control over any Centessa shares.

What is the significance of 'ownership of 5 percent or less' in the Centessa (CNTA) filing?

The Schedule 13G/A notes ownership of 5 percent or less of the class, confirming the reporting persons’ holdings have dropped below the 5% threshold that previously required a large shareholder disclosure.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/12/2026 - 12:07 PM Accepted by SEC EDGAR 08/12/2026 - 12:06 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 4)

Centessa Pharmaceuticals plc

(Name of Issuer)

Ordinary shares, nominal value 0.002 GBP per share

(Title of Class of Securities)

152309100

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 152309100

1

Names of Reporting Persons

Adage Capital Management, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP Number(s): 152309100

1

Names of Reporting Persons

Robert Atchinson

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP Number(s): 152309100

1

Names of Reporting Persons

Phillip Gross

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Centessa Pharmaceuticals plc
(b)	Address of issuer's principal executive offices: 3rd Floor, 1 Ashley Road, Altrincham, Cheshire, WA14 2DTUnited Kingdom
Item 2.
(a)	Name of person filing: This statement is filed by: (i) Adage Capital Management, L.P., a Delaware limited partnership ("ACM"), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership ("ACP"), with respect to the American Depositary Shares, each representing one ordinary share, nominal value (pound)0.002 per share ("Ordinary Shares") of Centessa Pharmaceuticals PLC, a limited liability company incorporated under the laws of England and Wales (the "Company") underlying the ADSs (as defined below) that were directly held by ACP; (ii) Robert Atchinson ("Mr. Atchinson"), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACA"), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACPGP"), general partner of ACP and (2) managing member of Adage Capital Partners LLC, a Delaware limited liability company ("ACPLLC"), general partner of ACM, with respect to the Ordinary Shares underlying the ADSs that were directly held by ACP; and (iii) Phillip Gross ("Mr. Gross"), as (1) managing member of ACA, managing member of ACPGP and (2) managing member of ACPLLC, general partner of ACM, with respect to the Ordinary Shares underlying the ADSs that were directly held by ACP. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party. There is no CUSIP number assigned to the Ordinary Shares. The CUSIP number 152309100 was assigned to the American Depositary Shares ("ADSs") of the Company, which was quoted on Nasdaq under the symbol "CNTA." Each ADS represented one Ordinary Share.
(b)	Address or principal business office or, if none, residence: The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.
(c)	Citizenship: ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States.
(d)	Title of class of securities: Ordinary shares, nominal value 0.002 GBP per share
(e)	CUSIP No.: 152309100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(b)	Percent of class: 0.0%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
	(ii) Shared power to vote or to direct the vote: The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
	(iii) Sole power to dispose or to direct the disposition of: The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
	(iv) Shared power to dispose or to direct the disposition of: The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Adage Capital Management, L.P.

Signature:	/s/ Robert Atchinson
Name/Title:	By: Adage Capital Partners LLC, its General Partner, By: Robert Atchinson, its Managing Member
Date:	08/12/2026

Robert Atchinson

Signature:	/s/ Robert Atchinson
Name/Title:	Robert Atchinson, individually
Date:	08/12/2026

Phillip Gross

Signature:	/s/ Phillip Gross
Name/Title:	Phillip Gross, individually
Date:	08/12/2026