[SCHEDULE 13G/A] Prothena Corporation plc SEC Filing

Rhea-AI Filing Summary

Prothena Corporation plc: Multiple related entities led by Logos Global and Dr. William Arsani jointly filed a Schedule 13G/A reporting zero beneficial ownership of the issuer's Ordinary Shares, representing 0% of the class. The filing states Logos Global acts as an investment adviser to funds (including a master fund) and identifies the general partner relationships among the reporting entities. The filers say they submitted the statement jointly but expressly disclaim membership in a group and disclaim beneficial ownership except to the extent of any pecuniary interest.

Insights

Securities Analyst

TL;DR: Filing reports no economic stake and therefore carries no immediate market impact.

The Schedule 13G/A shows Logos Global, affiliated entities and Dr. Arsani report 0 shares (0%) beneficial ownership of Prothena ordinary shares. As an investment adviser and general partner structure, the filing clarifies relationships and disclaims group membership and beneficial ownership except for pecuniary interest. For investors, the disclosure is administrative and contains no indication of a stake or control intent.

Corporate Governance Expert

TL;DR: Governance disclosure clarifies roles but reveals no ownership or voting influence.

The document documents reporting persons, their adviser/GP relationships, and explicit disclaimers of group status and beneficial ownership beyond pecuniary interest. It also contains the filers' certification that securities are not held to influence control. From a governance perspective, this is a routine transparency filing that does not signal activist intent or change in control.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

PROTHENA CORP PUBLIC LTD CO

(Name of Issuer)

Ordinary Shares

(Title of Class of Securities)

G72800108

(CUSIP Number)

06/30/2025

(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)

SCHEDULE 13G

CUSIP No. G72800108

1

Names of Reporting Persons

Logos Global Management LP

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 No. G72800108

1

Names of Reporting Persons

Logos Global Management GP LLC

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)

HC, OO

SCHEDULE 13G

CUSIP No. G72800108

1

Names of Reporting Persons

Logos Global Master Fund LP

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

CAYMAN ISLANDS

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)

PN

SCHEDULE 13G

CUSIP No. G72800108

1

Names of Reporting Persons

Logos GP LLC

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, OO

SCHEDULE 13G

CUSIP No. G72800108

1

Names of Reporting Persons

Arsani William

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: PROTHENA CORP PUBLIC LTD CO
(b)	Address of issuer's principal executive offices: 77 Sir John Rogerson's Quay, Block C, Grand Canal Docklands, Dublin 2, D02 VK60, Ireland
Item 2.
(a)	Name of person filing: Logos Global Management LP ("Logos Global") Logos Global Management GP LLC ("Logos Global GP") Logos Global Master Fund LP ("Global Fund") Logos GP LLC ("Logos GP") Arsani William Logos Global is the investment adviser to investment funds, including Global Fund. Logos Global GP is the general partner of Logos Global. Logos GP is the general partner of Global Fund. Dr. William is a control person of Logos Global, Logos Global GP and Logos GP. The reporting persons are filing this statement jointly but not as members of a group, and they expressly disclaim membership in a group. Each reporting person disclaims beneficial ownership of Common Stock except to the extent of that person's pecuniary interest therein. In addition, the filing of this Schedule 13G on behalf of the Global Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any Common Stock covered by this Schedule 13G.
(b)	Address or principal business office or, if none, residence: One Letterman Drive, Building C, Suite C3-350, San Francisco, California 94129
(c)	Citizenship: See Item 4 of the cover sheet for each reporting person.
(d)	Title of class of securities: Ordinary Shares
(e)	CUSIP No.: G72800108
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: Logos Global: 0 Logos Global GP: 0 Global Fund: 0 Logos GP: 0 Arsani William: 0
(b)	Percent of class: Logos Global: 0% Logos Global GP: 0% Global Fund: 0% Logos GP: 0% Arsani William: 0%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Logos Global: 0 Logos Global GP: 0 Global Fund: 0 Logos GP: 0 Arsani William: 0
	(ii) Shared power to vote or to direct the vote: Logos Global: 0 Logos Global GP: 0 Global Fund: 0 Logos GP: 0 Arsani William: 0
	(iii) Sole power to dispose or to direct the disposition of: Logos Global: 0 Logos Global GP: 0 Global Fund: 0 Logos GP: 0 Arsani William: 0
	(iv) Shared power to dispose or to direct the disposition of: Logos Global: 0 Logos Global GP: 0 Global Fund: 0 Logos GP: 0 Arsani William: 0
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. By signing below I certify that, to the best of my knowledge and belief, the securities referred to above 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.

Logos Global Management LP

Signature:	/s/ Arsani William
Name/Title:	Managing Partner
Date:	08/13/2025

Logos Global Management GP LLC

Signature:	/s/ Arsani William
Name/Title:	Managing Member
Date:	08/13/2025

Logos Global Master Fund LP

Signature:	/s/ Arsani William
Name/Title:	Managing Member of Logos GP LLC, General Partner of Logos Global Master Fund LP
Date:	08/13/2025

Logos GP LLC

Signature:	/s/ Arsani William
Name/Title:	Managing Member
Date:	08/13/2025

Arsani William

Signature:	/s/ Arsani William
Name/Title:	Reporting person
Date:	08/13/2025

Exhibit Information

EXHIBIT 99.1 - AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G

FAQ

Does Logos Global own any Prothena (PRTA) shares?

No. The filing reports 0 shares beneficially owned, representing 0% of the class.

Who are the reporting persons in the Schedule 13G/A for PRTA?

The reporting persons are Logos Global Management LP, Logos Global Management GP LLC, Logos Global Master Fund LP, Logos GP LLC, and William Arsani.

Did the filers form a group to act together regarding PRTA?

No. The filers state they are filing jointly but expressly disclaim membership in a group.

Does the filing indicate an intent to influence Prothena's control or management?

No. The filers certify that the securities were not acquired and are not held for the purpose of changing or influencing control.

What relationships among the reporting entities are disclosed?

The filing discloses that Logos Global is an investment adviser to funds including the master fund, Logos Global GP is general partner of Logos Global, and Logos GP is general partner of the master fund; Dr. Arsani is a control person of those entities.