Participation Notification by BlackRock Inc.

Participation notification by BlackRock Inc.

Brussels, Belgium – May 2, 2024 - 8:30 CEST

According to Belgian transparency legislation (Law of May 2, 2007), BlackRock Inc. (50 Hudson Yards, New York, NY, 10001, U.S.A.) recently sent to Syensqo the following transparency notification indicating that it crossed the threshold of 3%. Here is a summary of the move:

Date on which the threshold was crossed	Voting rights after the transaction	Equivalent financial instruments after the transaction	Total
April 25, 2024	2.99%	0.67%	3.67%

The notification, dated April 29, 2024, contains the following information:

Reason for the notification: Holding of voting securities upon first admission to trading
Notified by: BlackRock Inc. : A parent undertaking or a controlling person
Date on which the threshold is crossed: April 25, 2024
Threshold of direct voting rights crossed: 3% downwards
Denominator: 105,876,417
Additional information: The disclosure obligation arose due to voting rights attached to shares for BlackRock, Inc. going below 3%.
Persons subject to the notification requirement: see file attached

Transparency notifications and the full chain of controlled undertakings through which the holding is effectively held is available on the Investor Relations Section of Syensqo's website.

Media relations media.relations@syensqo.com Nathalye Van Ypersele +32 478 20 10 62 Perrine Marchal+32 478 32 62 72 Laetitia Schreiber+32 487 74 38 07

Investor Relations investor.relations@syensqo.com Sherief Bakr+44 7920 575 989 Bisser Alexandrov+33 6 07 63 52 80 Imtiyaz Lokhandwala+1 609 860 3959

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