FORM 4
[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).         	UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
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                      	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	                      	

1. Name and Address of Reporting Person *

M&G INVESTMENT MANAGEMENT LTD	2. Issuer Name and Ticker or Trading Symbol

Trinseo S.A. [ TSE ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable)

_____ Director                    __X__ 10% Owner
_____ Officer (give title below)    _____ Other (specify below)	
(Last)         (First)         (Middle)

10 FENCHURCH AVENUE	3. Date of Earliest Transaction (MM/DD/YYYY)

1/21/2021		
(Street)

LONDON, X0 EC3M 5AG
(City)       (State)       (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)

 	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. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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				
Common Stock 	1/21/2021 	 	S	  	3000 	D	$56.51 	7733044 	I 	Please see footnote (1)	

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)	
1. Title of Derivate Security
(Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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	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 of Derivative Security: 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					

Explanation of Responses:	
(1) 	The reported securities are held directly by certain funds advised by M&G Investment Management Limited, (i) M&G (Lux) Investment Funds 1 holds 2,537,620 ordinary shares in Trinseo S.A.; (ii) M&G Global Dividend Fund directly holds 3,615,353 ordinary shares in Trinseo S.A.; and (iii) LF Access Global Dividend Fund directly holds 1,580,071 ordinary shares in Trinseo S.A. The reported securities may be deemed beneficially owned for the purposes of Section 13(d) of the Securities Exchange Act 1934 by M&G Investment Management Limited as investment manager to these funds. The Reporting Person disclaims beneficial ownership of the securities for purposes of Rule 16a-1(a) (2) 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.	

Reporting Owners	
Reporting Owner Name / Address	Relationships	
	Director	10% Owner	Officer	Other	
M&G INVESTMENT MANAGEMENT LTD
10 FENCHURCH AVENUE
LONDON, X0 EC3M 5AG		X			

Signatures		
/s/ M&G INVESTMENT MANAGEMENT LIMITED, By: Tamara Postoj, Head of Regulatory Reporting		1/22/2021	
**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 control number.