Solvay SA

Major Shareholding Notification • Oct 21, 2025

Transparency notification Form TR-1 BE PART I

1) Status of the notification

2) Issuer

Name SOLVAY Identification number 0403-091-220

3) Reason for the notification

Acquisition or disposal of financial instruments that are treated as voting securities

+

4) Notification by

A parent undertaking or a controlling person

5) Persons subject to the notification requirement

Name	Address (for legal entities)
	c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware 19801, USA

6) Persons that dispose of voting rights (only to be filled in if art. 7 of the Law applies)

Name	Address (for legal entities)

Please continue entering the information in part II concerning the persons referred to in Sections 5 and 6

Part II

7) Date on which the threshold is crossed

14/10/2025 (DD/MM/YYYY)

8) Threshold that is crossed (in %)

If the holding has fallen below the lowest threshold, you have the option of not entering any numbers in Section 10

9) Denominator

Please enter the denominator before filling in the data

10) Notified details

A) Voting rights	Previous notification	After the transaction
	# of voting rights	# of voting rights		% of voting rights
Holders of voting rights		Linked to securities	Not linked to the securities	Linked to securities	Not linked to the securities
Morgan Stanley	0	0	0	0.00%	0.00%
Morgan Stanley & Co. International plc	0	34,972	0	0.03%	0.00%
Subtotal		34,972		0.03%
	34,972	0	0.03%	0.00%

Start with "groups" of holders. Add subtotals with $\Sigma$ , and then finish with the persons who are "alone". For groups, start with the ultimate controlling natural person or legal entity.

The totals, subtotals and % will be updated once you have clicked on CALCULATE>.

B) Equivalent financial instruments	nts After the transaction
Holders of equivalent financial instruments	Type of financial instrument	Expiration date	Exercise period or date	# of voting rights that may be acquired if the instrument is exercised	% of voting rights	Settlement
Morgan Stanley & Co. International plc	Retail Structured Product - Note	27/02/2026	At any time	3,752	0.00%	cash	-
Morgan Stanley & Co. International plc	Retail Structured Product - Note	02/07/2035	At any time	5,010	0.00%	cash	-
Morgan Stanley & Co. International plc	Retail Structured Product - Note	01/10/2035	At any time	5,268	0.00%	cash	-
Morgan Stanley & Co. International plc	Retail Structured Product - Note	17/08/2037	At any time	3,676	0.00%	cash	-
Morgan Stanley & Co. International plc	Retail Structured Product - Note	02/11/2037	At any time	3,548	0.00%	cash	-
Morgan Stanley & Co. International plc	Equity Call Options	19/12/2025	At any time	800	0.00%	physical	-
Morgan Stanley & Co. International plc	Equity Call Options	19/06/2026	At any time	316,100	0.30%	physical	-
Morgan Stanley & Co. International plc	Equity Put Options	17/10/2025	At any time	134,800	0.13%	physical	-
Morgan Stanley & Co. International plc	Equity Put Options	21/11/2025	At any time	133,400	0.13%	physical	-
Morgan Stanley & Co. International plc	Equity Put Options	19/12/2025	At any time	127,900	0.12%	physical	-
Morgan Stanley & Co. International plc	Equity Put Options	19/06/2026	At any time	756,300	0.71%	physical	-
Morgan Stanley & Co. International plc	Equity Put Options	18/12/2026	At any time	425,100	0.40%	physical	-
Morgan Stanley & Co. International plc	Equity Swap	27/11/2025	At any time	44,590	0.04%	cash	-
Morgan Stanley & Co. LLC	Right of recall over securities lending agreements	At any time	At any time	605,996	0.57%	physical	-
Morgan Stanley & Co. International plc	Right of recall over securities lending agreements	At any time	At any time	210,738	0.20%	physical	-
Prime Dealer Services Corp.	Right of recall over securities lending agreements	At any time	At any time	460,645	0.44%	physical	+
	TOTAL			3,237,623	3.06%

Done at Glasgow

The totals will be updated once you have clicked on

TOTAL (A & B)	# of voting rights	% of voting rights
	CALCULATE	3,272,595	3.09%

11) Full chain of controlled undertakings through which the holding is effectively held, if applicable

Please refer to Chain of Controlled Undertakings

12) In case of proxy voting for	or only one GM
Holder		will cease to hold / will hold again	0	voting rights as of	(DD/MM/YYYY)
13) Additional information

On 17/10/2025 (DD/MM/YYYY)

Name & capacity Ross Williams, Regulatory Operations Signature

For security reasons, the unsigned form in xlsx format should be transmitted to trp.fin@fsma.be. You can do this manually OR if you have MS Outlook at your disposal via the "Save & Send" button.

In addition, a signed copy in PDF format should also be transmitted.

Chain of controlled undertakings

Chain of controlled undertakings for Morgan Stanley & Co. International plc

• Morgan Stanley & Co. International plc, 25 Cabot Square, Canary Wharf, London, E14 4QA, UNITED KINGDOM is a direct holder and is a subsidiary of Morgan Stanley Investments (UK)
• Morgan Stanley Investments (UK), 20 Bank Street, Canary Wharf, London, E14 4AD, UNITED KINGDOM is an indirect holder and is a subsidiary of Morgan Stanley International Limited
• Morgan Stanley International Limited, 25 Cabot Square, Canary Wharf, London, E14 4QA, UNITED KINGDOM is an indirect holder and is a subsidiary of Morgan Stanley International Holdings Inc.
• Morgan Stanley International Holdings Inc., c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware, 19801, USA. is an indirect holder and is a subsidiary of the beneficial owner, Morgan Stanley

Chain of controlled undertakings for Morgan Stanley & Co. LLC

• Morgan Stanley & Co. LLC, c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware, 19801, USA. is a direct holder and is a subsidiary of Morgan Stanley Capital Management, LLC.
• Morgan Stanley Capital Management, LLC, c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware, 19801, USA. is an indirect holder and is a subsidiary of the beneficial owner, Morgan Stanley

Chain of controlled undertakings for Prime Dealer Services Corp.

• Prime Dealer Services Corp., c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware, 19801, USA is a direct holder and is a subsidiary of Morgan Stanley & Co. LLC
• Morgan Stanley & Co. LLC, c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware, 19801, USA. is a direct holder and is a subsidiary of Morgan Stanley Capital Management, LLC.
• Morgan Stanley Capital Management, LLC, c/o The Corporation Trust Company (DE), Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware, 19801, USA. is an indirect holder and is a subsidiary of the beneficial owner, Morgan Stanley

Morgan Stanley is not a controlled entity.