Intimation regarding closure of trading window for the quarter and half year ending September 30, 2026 is attached herewith.

Hindustan Oil Exploration Company Limited ‘Lakshmi Chambers’, 192, St. Mary’s Road, Alwarpet, Chennai - 600 018. INDIA. : 91 (044) 66229000 ● Fax: 91 (044) 66229011 / 66229012 E-mail: contact@hoec.com ● Website: www.hoec.com CIN: L11100GJ1996PLC029880 September 30, 2026 By Online The Listing Department The Corporate Relationship Department National Stock Exchange of India Ltd., BSE Limited “Exchange Plaza”, 1st Floor, P. Jeejeebhoy Towers, Bandra Kurla Complex, Bandra (East), Dalal Street, Mumbai – 400 051 Mumbai – 400 001 Stock Code: HINDOILEXP Stock Code: 500186 Dear Sir/Madam, Sub: Intimation of Closure of Trading Window This is to inform you that pursuant to SEBI (Prohibition of Insider Trading) Regulations, 2015, as amended from time to time, read with the Company’s code of conduct for regulating, monitoring and trading by insiders, the trading window for dealing in shares of the Company shall stand closed to Directors, employees and other Designated Persons of the Company from October 01, 2026 till 48 hours after the declaration of the unaudited financial results for the quarter and half year ending September 30, 2026. We request you to kindly take our aforesaid submission on record. Thanking you, Yours Sincerely, For Hindustan Oil Exploration Company Limited G. Josephin Daisy Company Secretary and Compliance Officer Registered Office: ‘HOEC HOUSE’, Tandalja Road, Off Old Padra Road, Vadodara - 390 020. INDIA. : 91 (0265) 2330766 ● E-mail: contact@hoec.com ● Website: www.hoec.com