Change in Auditors

OIL AND NATURAL GAS CORPORATION LIMITED COMPANY SECRETARIAT ONGC/CS/SE/2026-27 08.09.2026 National Stock Exchange of India Ltd. BSE Limited Listing Department Corporate Relationship Department Exchange Plaza Phiroze Jeejeebhoy Towers Bandra-Kurla Complex, Bandra (E) Dalal Street, Fort Mumbai – 400 051 Mumbai – 400 001 Symbol-ONGC; Series – EQ BSE Security Code No: 500312 NCD: 959881 Sub: Appointment of Statutory/Joint Statutory Auditors by C&AG for Financial Year 2026-27 Madam/ Sir, Pursuant to Regulation 30 read with Schedule III of SEBI (Listing Obligations and Disclosure Requirements) Regulations, 2015, it is hereby informed that a letter has been received from the office of Comptroller & Auditor General of India (C&AG) on 7th September, 2026 conveying appointment of the following Chartered Accountants Firms/ Limited Liability Partnership as Statutory/ Joint Statutory Auditor(s) for the Financial year 2026-27: 1. M/s T R Chadha & Co LLP 2. M/s P K F Sridhar & Santhanam LLP 3. M/s Suri & Co 4. M/s A R & Co Brief profiles as per SEBI Circular are enclosed at Annexure-A. This is for your information and record, please. Thanking You, Yours Sincerely, for Oil and Natural Gas Corporation Ltd. (Shashi Bhushan Singh) Company Secretary & Compliance Officer Regd. Office: Plot No 5A-5B, Nelson Mandela Marg, Vasant Kunj, New Delhi-110070 Phone: 011-2675 4073, 011-2675 4085 EPABX: 2675 0111, 2629000 CIN: L74899DL1993GOI054155 Website: www.ongcindia.com Email: secretariat@ongc.co.in Annexure-A To, 8th August 2026 ONGC Ltd. Corporate Accounts, Delhi Sub: Brief Profile of T R Chadha & Co LLP T R Chadha & Co LLP (TRC) is a prominent and well-established firm of Chartered Accountants registered with the Institute of Chartered Accountants of India (ICAI). T R Chadha & Co LLP was founded in 1946 (over 80 years old) and registered in India vide Registration number 006711N/N500028. The firm has its registered office at B-30, Connaught Place, Kuthiala Building, New Delhi - 110001 apart from 10 other full-fledged offices in various cities in India including at Mumbai, Chennai, Ahmedabad, Hyderabad, Bengaluru, Gurgaon, Noida, Pune, Vadodara and Tirupati. TRC has more than 1000 people including 22 Full-Time FCA partners and over 160 Qualified Chartered Accountants working with them. The firm has extensive experience in providing Audit & Assurance, Advisory, Governance & Risk Services and Taxation & Regulatory Services to its clients. It is amongst the largest and highly reputed audit firms in India and are auditors for several large companies including some of the large listed companies in India across diverse sectors. TRC has dynamic experience of more than 6 decades in auditing large Central Public Sector Undertakings (PSUs) including Indian Oil Corporation Ltd, Bharat Petroleum Corporation Limited, NTPC Limited, Steel Authority of India Limited, Power Grid Corporation of India Limited, REC Limited, etc. TRC has also been Central Statutory auditors of various banks including State Bank of India, Canara Bank, Bank of Baroda, Standard Chartered Bank, etc. TRC is registered with various Regulators including Comptroller and Auditor General of India (C & A G), Reserve Bank of India (RBI), Securities & Exchange Board of India (SEBI), IRDAI, PFRDA, and carry out various audits and inspections on their behalf. TRC is also registered with Public Company Accounting Oversight Board (PCAOB), USA. The firm is certified with ICAI’s Peer Review & AQMM Maturity Level 4. TRC strongly believes in ensuring quality and ethics without fail. With Regards, Vikas Kumar, Sr. Partner & CEO T R Chadha & Co LLP, A limited liability partnership with LLP Identification No. AAF-3926 Mumbai Branch Office: E 2001-02, Lotus Corporate Park, Off Western Express Highway, Ram Mandir Station Road, Goregaon East, Mumbai 400063 Ph: +91 22 49669000 | E mail: mumbai@trchadha.com | Website: www.trchadha.com Corporate/ Regd. Office: B-30, Connaught Place, Kuthiala Building, New Delhi – 110001 | Ph: 43259900 | E-mail: delhi@trchadha.com Offices: Abu Dhabi | Ahmedabad | Bengaluru | Chennai | Gurugram | Hyderabad | Mumbai | New Delhi | Noida | Pune | Tirupati | Vadodara SURI & CO. FIRM PROFILE CHARTERED ACCOUNTANTS ABOUT US Suri & Co, established in 1939 by Late Shri S. Suriyanarayanan, is a distinguished Chartered Accountancy firm built on integrity, trust, and 8 DECADES professionalism. Over 85 years, the firm has grown to 320+ professionals and 13 full-time CA Partners across 4 states and 8 centres. We deliver of trust, integrity & professionalism since 1939 Statutory, IFRS Convergence, Forensic, Tax, and GST Audits, alongside Risk Management and Advisory services including Transaction Advisory, Due Diligence, and Business & Security Valuation. Our BFSI expertise spans 50+ years of bank branch audit experience, central statutory audits of 14 public sector and 4 private banks, audits of 3 insurance companies, and audits of NBFCs and mutual fund asset management companies. The firm also brings STATES 53 years of statutory audit experience of Public Sector Undertakings (PSUs). Backed by technology platforms such as XcelAudit, CaseWare, IDEA, and Thomson Reuters, and empanelments with the CAG, RBI, Audit Bureau of Circulations, and the PCAOB, Suri & Co delivers dedicated, ethical, technology-driven solutions tailored to each client's needs. CENTRES SERVICES Assurance FULL-TIME CA PARTNERS Statutory Audits · Co-operative Society Audits · Transfer Pricing & Forensic Audits · Tax Audit (Sec 44AB) · IFRS Convergence · GST & Information System Audits 320+ Risk Management WORKFORCE Risk-Based Internal Audits · Revenue Leakage Audits · Concurrent Audits · System Audits · Internal Control over Financial Reporting (ICFR) Advisory & Litigation BRANCH NETWORK Reporting & Strategic Consulting · Transaction Advisory · Non-Resident Taxation · Due Diligence · Tribunal Litigation (IT & GST) · Business & Security Valuation • Chennai (HO) Compliance • Mumbai • Bangalore Income Tax & Transfer Pricing Filings · GST Registration, Returns & Reconciliation · Companies Act & FEMA Compliance · End-to-End Accounting & MIS • Coimbatore K S L NETWORK • Madurai • Kochi Suri & Co is a founding member of the K S L Network, formed together with K C Mehta & Co LLP and Laxminiwas & Co — a homegrown, multi- • Thiruvananthapuram disciplinary Indian CA network. The Network brings together 900+ professionals and 47 partners with 180+ years of combined firm experience across • Coonoor 17 offices spanning Ahmedabad, Bengaluru, Chennai, Coimbatore, Coonoor, Hyderabad, Kochi, Madurai, Mumbai, Mysuru, Thiruvananthapuram, Vadodara, and Visakhapatnam. CONTACT INDUSTRY EXPERIENCE 443 & 445, Guna Complex, Anna Salai, Teynampet, Chennai 600018 Automobiles | Industrial Linings | Steel Rolling | Sugar | Energy Generation & Distribution | Insulation, Energy Batteries | Heavy Engineering | Plantations | Biotech | 044-28251140 / 1150 Natural Products | Fertilizers | Petroleum Products | Textiles | Auto Components and Accessories | Forgings and Castings | Paper and Boards | Distillery and Chemical chennai@suriandco.com Products | Transformers and Switchgears | Light Engineering | Heat Exchangers | Estates | Processed Food Products | Fruit based Beverages | Solvent Extraction | Leather & Leather Products | Garment Manufacturing | Infrastructure development | Health Foods | Rubber Footwear A.R. & CO. Head Office Chartered Accountants A-403, Gayatri Apartment, Airlines Group Housing Society, Plot No.27, Sector-10, Dwaraka, New Delhi-110075 Ph No. 9810195084, 9810444051 E-mail: ar_co1981@yahoo.co.in pawankgoel1@gmail.com M/s A.R. & Co. Chartered Accountants was established in 1981 having an experience of more than 44 years having a team of experienced Professionals and other support staff present across the country operating in the fields of taxation, auditing, consultancy, litigation, assurance & advisory, FDD, M&A advisory, listing advisory (having participated in vari [Showing first 8,000 characters — download PDF for full document]