IRPC Annual Report 2023

Relationship with Businesses of Major Shareholders IRPC’s major shareholder is PTT Public Company Limited (PTT), a fully integrated petroleum and petrochemical business operator with upstream to downstream supply chain through PTT’s own and others’ business through its subsidiaries, namely, petroleum exploration and production, oil refining, and petrochemical businesses. Currently, PTT is the major shareholder of Thailand’s three refineries, comprising PTT Global Chemical Public Company Limited (45.18 percent), Thaioil Public Company Limited (45.03 percent), and IRPC Public Company Limited (45.05 percent). In petroleum and petrochemical business operations, IRPC has transactions and cooperates with PTT and its subsidiaries. For example, IRPC purchases most crude oil through PTT for efficiency enhancement and cost reduction, manages part of oil and/ or product price hedging through PTT, and receives and provides financial assistance for mutual liquidity management, etc. In addition, IRPC has transactions associated with the trade in feedstocks, petroleum products and petrochemical products, with the PTT Group of companies. Shareholders List of Top 10 shareholders of the company as of the book closing date February 22, 2023 are as follows: Notes: (1) PTT Public Company Limited, as the company’s major shareholder, takes part in determining the management policy and operations of the company. This has been approved by IRPC’s Board of Directors. As of December 31, 2023, four out of 14 members of the company’s Board are directors or executives of PTT Public Company Limited. (2) Thai NVDR Company Limited is a subsidiary of the Stock Exchange of Thailand, which operates business by issuing Non-Voting Depository Receipt (NVDR) securities listed on the Stock Exchange of Thailand. Such securities are for sale to investors and the proceeds from the sale of NVDR are then invested in Thai underlying securities that are listed on the Stock Exchange. Investors who are NVDR holders are entitled to benefits, such as dividends, rights to subscribe to new shares just like shareholders of a listed company, but do not have voting rights at the shareholders’ meeting. To learn more about Thai NVDR, go to: www.set.or.th No. Shareholder Number of shares Shareholding (Percentage) 1. PTT Public Company Limited (1) 9,206,674,600 45.05% 2. Thai NVDR Company Limited (2) 1,082,485,273 5.30% 3. Siam Management Holding Company Limited 613,020,000 3.00% 4. Social Security Office 403,836,400 1.98% 5. SOUTH EAST ASIA UK (TYPE C) NOMINEES LIMITED 301,027,067 1.47% 6. Mr. Suphot Sapthaweechaikul 195,500,000 0.96% 7. STATE STREET EUROPE LIMITED 153,011,827 0.75% 8. N.C.B.TRUST LIMITED-POLUNIN DEVELOPING COUNTRIES FUND, LLC 123,503,393 0.60% 9. Mr. Woraphong Asawanives 94,389,200 0.46% 10. Bualuang Infrastructure Retirement Mutual Fund 76,666,500 0.38% 97 Structure and Business Operations of IRPC 56-1 ONE REPORT 2023

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