To Determine the Dates for Exercising the CDDR No.25

-TRANSLATION- No. 1000/092/2010 June 2, 2010 Subject : To Determine the Dates for Exercising the Voluntary Conversion of Depository Receipts in The Benefits of The Convertible Debentures of The Bangchak Petroleum Public Company Limited (BCP141A) - June 30, 2010 Attention : President of The Stock Exchange of Thailand Reference : 1. Terms and Conditions of the Depository Receipts on The Bangchak Petroleum Public Company Limited's Convertible Debentures (Terms and Conditions of BCP141A) 2. Terms and Conditions Stipulating the Rights and Duties of the Debenture Issuer and the Debentureholders Subordinated Convertible Debentures of The Bangchak Petroleum Public Company Limited Series 1/2547, Due A.D.2014 (Terms and Conditions of BCP@A) Attachment : Detailed Information for Notifications of Exercise of the Conversion of Depository Receipt in The Benefits of The Convertible Debentures of Bangchak Petroleum Public Company Limited As The Bangchak Petroleum Public Company Limited (Company) has issued and offered its Subordinated Convertible Debentures Series 1/2547, Due A.D.2014 to Siam DR Co., Ltd. (Siam DR) for the purpose of being the underlying asset for the issuance of baht 4,000,000,000 of the Depository Receipts in The Benefits of The Convertible Debentures of The Bangchak Petroleum Public Company Limited (BCP141A), which Siam DR issued to the investors on January 29, 2004. According to Clause 3.6 of the Terms and Conditions of BCP141A with respect to the rights of Voluntary Conversion, the CDDR holders have the right to redeem the depository receipts (BCP141A) to convertible debentures (BCP@A) and then to ordinary shares (BCP) (except for the foreign debentureholders, who may be subject to the limitation on registration in the Company's shareholder registry as stated in Clause 11.6 of the Terms and Conditions of BCP@A). The Voluntary Conversion may be made on quarterly basis on the 30th day of March, June, September, December each year. For this conversion, the exercise is on June 30, 2010 at the conversion price baht 14.30. The Company would like to inform SET that the BCP141A holders have to notify the intention for the Voluntary Conversion during June 23, 2010 - June 29, 2010 via Bualuang Securities Public Company Limited, the Company Agent for Accepting Exercise of the Conversion of BCP141A. (The detailed information is as attachment.) The BCP141A holders can download the BCP141A conversion manual and the form of notice of intention for Voluntary Conversion from the Company's website. (www.bangchak.co.th) Please be informed accordingly. Yours sincerely, -signed- (Surachai Kositsareewong) Executive Vice President Accounting and Finance Corporate Planning and Investor Relation Office Tel : 0-2335-4583 CC : Managing Director, Siam DR Co., Ltd. Detailed Information for Notifications of Exercise of BCP141A Agent Accepting Notifications of :Bualuang Securities Public Company Exercise of BCP141A (the Agent) Limited (BLS) 191 Silom Complex Office Building, 29/F, Silom Road, Silom, Bangrak, Bangkok 10500 Tel. 0-2618-1140, 0-2618-1141 Fax 0-2618-1120 Contact persons : Khun Trinop Kumnerdkarn or Khun Jirawat Sittidech Account of BLS for Accepting : 224-000000035-5 for local BCP141A holders Transfer of BCP141A 224-000000035-5 for foreign BCP141A holders Date of Exercise : Every 30th day of March, June, September and December of each year throughout the term of BCP141A. The first day of exercise is on June 30, 2004 and the last day is on September 30, 2013. In case the date of exercise is a non-banking day, the date of exercise will be the next banking day. For this conversion, the exercise is on June 30, 2010. Period of Exercise : BCP141A holders must notify the Agent during the working hours of the Agent from 9.00 hours until 16.00 hours within 5 working days prior to each date of exercise. For this conversion, the notification period is during on the June 23,2010 - June 29, 2010. Method of Exercise : BCP141A holders notify the Agent, together with the documents as follows : 1. Form of intention to exercise the right of BCP141A redemption (the Notification Form) together with the power of attorney. 2. In case of scrip system, BCP141A holders must submit the endorsed scrips in accordance with the number specified in the Notification Form. In case of scripless system, BCP141A holders will notify through the Depositor and transfer BCP141A to the securities deposit account of the Agent. 3. In case of juristic person, a copy of the Affidavit issued by Ministry of Commerce and certified by the authorized person(s). 4. In case of individual, a copy of identification card of the BCP141A holder. The Notification Form : BCP141A holders would be able to obtain and submit the Notification Form to the office of the Agent. Fee : None.