To Determine the Dates for Exercising the CSDR

-TRANSLATION- No. 1000 / 055 / 2007 March 15, 2007 Subject : To Determine the Dates for Exercising the Voluntary Conversion of Depository Receipt for Common Shares of The Bangchak Petroleum Public Company Limited - April 5, 2007 Attention : President of The Stock Exchange of Thailand Reference : Terms and Conditions of the Depository Receipt for Common Shares of Bangchak Petroleum Public Company Limited Attachment : Detailed Information for Notifications of Exercise of the Conversion of Depository Receipt for Common Shares of Bangchak Petroleum Public Company Limited - April 5, 2007 As The Bangchak Petroleum Public Company Limited (Company) has issued and offered its ordinary shares to Siam DR Co., Ltd. (Siam DR) for the purpose of being the underlying asset for the issuance of 520.06 units of the Depository Receipt for Common Shares of The Bangchak Petroleum Public Company Limited (CSDR), which Siam DR issued to the investors on January 29, 2004. According to Clause 3.8 of the Terms and Conditions of CSDR with respect to the rights of Voluntary Conversion, the CSDR holders have the right to wholly or partly convert CSDR to ordinary shares (except for the CSDR foreign holders, who may be subject to the limitation on registration in the Company's shareholder registry as stated in Clause 3.8 (4) (d) of the Terms and Conditions of CSDR). The Voluntary Conversion may be made on quarterly basis on the 5th of January, April, July, October each year. For this conversion, the exercise is on April 5, 2007 at the conversion ratio of 1 CSDR for 1 ordinary share. The Company would like to inform SET that the CSDR holders have to notify the intention for the Voluntary Conversion during March 29 - April 4, 2007 via Bualuang Securities Public Company Limited, the Company Agent for Accepting Exercise of the Conversion of CSDR. (The detailed information is as attachment.) Please be informed accordingly. Yours sincerely, -signed- (Patiparn Sukorndhaman) Senior Executive Vice President Accounting and Finance Corporate Planning and Investor Relation Office Tel : 0-2335-4583 CC : 1. Managing Director, Siam DR Co., Ltd. 2. Managing Director, Thailand Securities Depository Co, Ltd. 3. Managing Director, Bualuang Securities Public Company Limited Detailed Information for Notifications of Exercise of CSDR - April 5, 2007 Agent Accepting Notifications : Bualuang Securities Public Company Limited of Exericse of CSDR (the Agent) (BLS) 191 Silom Complex Office Building, 29/F, Silom Road, Silom, Bangrak, Bangkok 10500 Tel. 0-2231-3777 Fax 0-2266-6967 Contact persons : Khun Trinop Kumnerdkarn or Khun Pakamas Sukjai Account of BLS for Accepting : 224-030002-6 for local DR's holders Transfer of CSDR 224-930001-5 for foreign DR's holders Date of Exercise : Every 5th of January, April, July and October of each year throughout the term of CSDR. The first day of exercise is on April 5, 2005 and the last day is on October 5, 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 April 5, 2007 Period of Exercise : CSDR 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 March 29 - April 4, 2007. Method of Exercise : CSDR holders notify the Agent, together with the documents as follows : 1. Form of Notifications of Exercise of CSDR (the Notification Form) together with the power of attorney. 2. In case of scrip system, CSDR holders must submit the endorsed scrips in accordance with the number specified in the Notification Form, together with the cheque made payable to "Bualuang Securities Public Company Limited" In case of scripless system, CSDR holders will notify through the Depositor and transfer CSDR to the securities deposit account of the Agent, together with the cheque made payable to "Bualuang Securities Public Company Limited" 3. In case of juristic person, copy of the Affidavit issued by Ministry of Commerce and certified by the authorized person(s). 4. In case of individual, copy of identification card of the CSDR holder. The Notification Form : CSDR holders would be able to obtain and submit the Notification Form to the office of the Agent. Fee and payment methods : CSDR holders should pay a brokerage fee of 0.25% of offering price at 13.00 Bahts per unit and VAT of brokerage by cheque or cashier cheque, within Bangkok clearing house,crossed and made account payee to "Bualuang Securities Public Company Limited" (If notify in the last day of notification period, on April 4, 2007, the Agent would accept payment by cashier cheque only.