CastleKnight/Aaron Weitman discloses 7.8% stake in Trinseo PLC

Rhea-AI Filing Summary

CastleKnight-related entities and Aaron Weitman reported ownership of 2,766,226 ordinary shares of Trinseo PLC, representing 7.8% of the class. The filing shows the stake is held with shared voting and shared dispositive power (no sole voting or sole dispositive power reported). The reporting group identifies six related entities/persons that each report the same aggregate amount and percent, and the filing includes exhibits for a joint filing agreement and control-person identification. The statement also certifies the position is not held to influence control of the issuer.

Positive

• Clear disclosure of a material stake: 2,766,226 shares representing 7.8% of the class are explicitly reported
• Shared voting and dispositive power disclosed, improving transparency about who can influence or dispose of the shares
• Joint filing and control-person exhibits included, indicating coordinated and compliant reporting among related entities

Negative

• None.

Insights

Financial Analyst

TL;DR: A 7.8% stake reported by affiliated CastleKnight entities signals a sizeable passive holding; disclosure improves market transparency.

The disclosure reports 2,766,226 ordinary shares (7.8%) held with shared voting and dispositive power across CastleKnight entities and Aaron Weitman. Because the filing is on Schedule 13G with a certification that the holdings are not for control purposes, the market should treat this as a substantial but passive stake. For investors, the important data points are the absolute share count, the 7.8% ownership, and the absence of sole voting or sole dispositive authority, which reduces immediate corporate governance implications.

Corporate Governance Expert

TL;DR: The group-level disclosure and joint filing exhibit are appropriate for coordinated reporting; no indication of control intent.

The filing lists multiple related reporting persons filing jointly and references exhibits for joint filing arrangements and control-person identification. All reporting persons state shared voting/dispositive power of 2,766,226 shares and include an Item 10 certification that the holdings are not intended to influence control. From a governance perspective, the structure warrants monitoring but, as disclosed, does not assert control or triggering governance changes.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Trinseo PLC

(Name of Issuer)

Ordinary Shares, par value $0.01 per share

(Title of Class of Securities)

G9059U107

(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. G9059U107

1

Names of Reporting Persons

CastleKnight 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 2,766,226.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,766,226.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,766,226.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No. G9059U107

1

Names of Reporting Persons

CastleKnight Fund 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 2,766,226.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,766,226.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,766,226.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP No. G9059U107

1

Names of Reporting Persons

CastleKnight 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 2,766,226.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,766,226.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,766,226.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. G9059U107

1

Names of Reporting Persons

CastleKnight 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 2,766,226.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,766,226.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,766,226.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP No. G9059U107

1

Names of Reporting Persons

Weitman Capital 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

NEW JERSEY

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,766,226.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,766,226.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,766,226.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP No. G9059U107

1

Names of Reporting Persons

Aaron Weitman

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 2,766,226.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,766,226.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,766,226.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Trinseo PLC
(b)	Address of issuer's principal executive offices: 440 East Swedesford Road, Suite 301, Wayne, PA 19087
Item 2.
(a)	Name of person filing: CastleKnight Master Fund LP CastleKnight Fund GP LLC CastleKnight Management LP CastleKnight Management GP LLC Weitman Capital LLC Aaron Weitman
(b)	Address or principal business office or, if none, residence: CastleKnight Master Fund LP Maples Corporate Services Limited P.O. Box 309 Ugland House Grand Cayman KY1-1104 Cayman Islands CastleKnight Fund GP LLC 888 Seventh Avenue, 24th Floor New York, New York 10019 United States of America CastleKnight Management LP 888 Seventh Avenue, 24th Floor New York, New York 10019 United States of America CastleKnight Management GP LLC 888 Seventh Avenue, 24th Floor New York, New York 10019 United States of America Weitman Capital LLC c/o Aaron Weitman c/o CastleKnight Management LP 888 Seventh Avenue, 24th Floor New York, New York 10019 United States of America Aaron Weitman c/o CastleKnight Management LP 888 Seventh Avenue, 24th Floor New York, New York 10019 United States of America
(c)	Citizenship: CastleKnight Master Fund LP - Cayman Islands CastleKnight Fund GP LLC - Delaware CastleKnight Management LP - Delaware CastleKnight Management GP LLC - Delaware Weitman Capital LLC - New Jersey Aaron Weitman - United States of America
(d)	Title of class of securities: Ordinary Shares, par value $0.01 per share
(e)	CUSIP No.: G9059U107
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: CastleKnight Master Fund LP - 2,766,226 CastleKnight Fund GP LLC - 2,766,226 CastleKnight Management LP - 2,766,226 CastleKnight Management GP LLC - 2,766,226 Weitman Capital LLC - 2,766,226 Aaron Weitman - 2,766,226
(b)	Percent of class: CastleKnight Master Fund LP - 7.8% CastleKnight Fund GP LLC - 7.8% CastleKnight Management LP - 7.8% CastleKnight Management GP LLC - 7.8% Weitman Capital LLC - 7.8% Aaron Weitman - 7.8%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: CastleKnight Master Fund LP - 0 CastleKnight Fund GP LLC - 0 CastleKnight Management LP - 0 CastleKnight Management GP LLC - 0 Weitman Capital LLC - 0 Aaron Weitman - 0
	(ii) Shared power to vote or to direct the vote: CastleKnight Master Fund LP - 2,766,226 CastleKnight Fund GP LLC - 2,766,226 CastleKnight Management LP - 2,766,226 CastleKnight Management GP LLC - 2,766,226 Weitman Capital LLC - 2,766,226 Aaron Weitman - 2,766,226
	(iii) Sole power to dispose or to direct the disposition of: CastleKnight Master Fund LP - 0 CastleKnight Fund GP LLC - 0 CastleKnight Management LP - 0 CastleKnight Management GP LLC - 0 Weitman Capital LLC - 0 Aaron Weitman - 0
	(iv) Shared power to dispose or to direct the disposition of: CastleKnight Master Fund LP - 2,766,226 CastleKnight Fund GP LLC - 2,766,226 CastleKnight Management LP - 2,766,226 CastleKnight Management GP LLC - 2,766,226 Weitman Capital LLC - 2,766,226 Aaron Weitman - 2,766,226
Item 5.	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.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Please see Exhibit B attached hereto.
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 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.

CastleKnight Master Fund LP

Signature:	By: CastleKnight Fund GP LLC, its general partner, By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:	Aaron Weitman/Manager
Date:	08/14/2025

CastleKnight Fund GP LLC

Signature:	By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:	Aaron Weitman/Manager
Date:	08/14/2025

CastleKnight Management LP

Signature:	By: CastleKnight Management GP LLC, its general partner, By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:	Aaron Weitman/Manager
Date:	08/14/2025

CastleKnight Management GP LLC

Signature:	By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:	Aaron Weitman/Manager
Date:	08/14/2025

Weitman Capital LLC

Signature:	/s/ Aaron Weitman
Name/Title:	Aaron Weitman/Manager
Date:	08/14/2025

Aaron Weitman

Signature:	/s/ Aaron Weitman
Name/Title:	Aaron Weitman
Date:	08/14/2025

Comments accompanying signature: * Each Reporting Person disclaims beneficial ownership of the reported securities except to the extent of his or its pecuniary interest therein, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

Exhibit Information

[Exhibit A - Joint Filing Agreement] [Exhibit B - Control Person Identification]

FAQ

How many Trinseo PLC (TSE) shares did the CastleKnight group report owning?

They reported beneficial ownership of 2,766,226 shares of Trinseo PLC.

What percent of Trinseo's class does 2,766,226 shares represent?

The reported amount represents 7.8% of the class of ordinary shares.

Do the reporting persons have sole voting or dispositive power over these TSE shares?

No. The filing shows 0 sole voting power and 0 sole dispositive power; all power is reported as shared.

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

The reporting persons are CastleKnight Master Fund LP, CastleKnight Fund GP LLC, CastleKnight Management LP, CastleKnight Management GP LLC, Weitman Capital LLC, and Aaron Weitman.

Is the reported stake intended to influence control of Trinseo PLC?

The filing includes a certification stating the securities were not acquired and are not held to change or influence control of the issuer.