<div id="readability-page-1" class="page"><div>RNS Number : 7473Q Costain Group PLC 28 January 2026 TR-1: Standard form for notification of major holdings1. Issuer DetailsISINGB00B64NSP76Issuer NameCOSTAIN GROUP PLCUK or Non-UK IssuerUK2. Reason for NotificationAn acquisition or disposal of voting rights3. Details of person subject to the notification obligationNameUBS Group AG-Investment Bank &amp; Global Wealth ManagementCity of registered office (if applicable)LondonCountry of registered office (if applicable)United Kingdom4. Details of the shareholder<div><table><tbody><tr><td>Name</td><td>UBS AG</td></tr><tr><td>City of registered office</td><td>London</td></tr><tr><td>Country of registered office</td><td>United Kingdom</td></tr></tbody></table></div>5. Date on which the threshold was crossed or reached26-Jan-20266. Date on which Issuer notified28-Jan-20267. Total positions of person(s) subject to the notification obligation<div><table><tbody><tr><td></td><td>% of voting rights attached to shares (total of 8.A)</td><td>% of voting rights through financial instruments (total of 8.B 1 + 8.B 2)</td><td>Total of both in % (8.A + 8.B)</td><td>Total number of voting rights held in issuer</td></tr><tr><td>Resulting situation on the date on which threshold was crossed or reached</td><td>7.933702</td><td>0.000000</td><td>7.933702</td><td>21160366</td></tr><tr><td>Position of previous notification (if applicable)</td><td>8.014094</td><td>0.000000</td><td>8.014094</td><td></td></tr></tbody></table></div>8. Notified details of the resulting situation on the date on which the threshold was crossed or reached8A. Voting rights attached to shares<div><table><tbody><tr><td>Class/Type of shares ISIN code(if possible)</td><td>Number of direct voting rights (DTR5.1)</td><td>Number of indirect voting rights (DTR5.2.1)</td><td>% of direct voting rights (DTR5.1)</td><td>% of indirect voting rights (DTR5.2.1)</td></tr><tr><td>GB00B64NSP76</td><td></td><td>21160366</td><td></td><td>7.933702</td></tr><tr><td>Sub Total 8.A</td><td colspan="2">21160366</td><td colspan="2">7.933702%</td></tr></tbody></table></div>8B1. Financial Instruments according to (DTR5.3.1R.(1) (a))<div><table><tbody><tr><td>Type of financial instrument</td><td>Sub Total 8.B1</td></tr><tr><td>Expiration date</td><td colspan="2"></td></tr><tr><td>Exercise/conversion period</td><td></td></tr><tr><td>Number of voting rights that may be acquired if the instrument is exercised/converted</td><td></td></tr><tr><td>% of voting rights</td></tr></tbody></table></div>8B2. Financial Instruments with similar economic effect according to (DTR5.3.1R.(1) (b))<div><table><tbody><tr><td>Type of financial instrument</td><td>Sub Total 8.B2</td></tr><tr><td>Expiration date</td><td colspan="3"></td></tr><tr><td>Exercise/conversion period</td><td></td></tr><tr><td>Physical or cash settlement</td><td></td></tr><tr><td>Number of voting rights</td></tr><tr><td>% of voting rights</td></tr></tbody></table></div>9. Information in relation to the person subject to the notification obligation2. Full chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held starting with the ultimate controlling natural person or legal entities (please add additional rows as necessary)<div><table><tbody><tr><td>Ultimate controlling person</td><td>Name of controlled undertaking</td><td>% of voting rights if it equals or is higher than the notifiable threshold</td><td>% of voting rights through financial instruments if it equals or is higher than the notifiable threshold</td><td>Total of both if it equals or is higher than the notifiable threshold</td></tr><tr><td>UBS Group AG (Chain 1)</td><td></td><td></td><td></td><td></td></tr><tr><td>UBS Group AG (Chain 1)</td><td>UBS AG</td><td>7.933702</td><td></td><td>7.933702%</td></tr></tbody></table></div>10. In case of proxy votingName of the proxy holderThe number and % of voting rights heldThe date until which the voting rights will be held11. Additional Information12. Date of Completion28-Jan-202613. Place Of CompletionZurich, SwitzerlandThis information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact rns@lseg.com or visit www.rns.com.RNS may use your IP address to confirm compliance with the terms and conditions, to analyse how you engage with the information contained in this communication, and to share such analysis on an anonymised basis with others as part of our commercial services. For further information about how RNS and the London Stock Exchange use the personal data you provide us, please see our Privacy Policy. END HOLPPUMAGUPQGUR</div></div>

COST

Costain Group PLC announced a notification of major holdings by UBS Group AG, which acquired 7.93% of the voting rights in the company as of January 26, 2026. The notification was made on January 28, 2026, indicating that UBS AG holds a total of 2,116,036 shares. This acquisition reflects a change from the previous holding of 8.01%. The information is provided by RNS, the news service of the London Stock Exchange.

REG - Costain Group PLC - Holding(s) in Company