Thailand-based PTT Exploration and Production Public Co. Ltd. (PTTEP) recently announced a US$2.5 billion acquisition of a stake in Block 61 in Oman. While PTTEP's stand-alone credit profile can accommodate the proposed transaction, the acquisition will weigh on the creditworthiness of PTT Public Co. Ltd. (PTT), PTTEP's parent company, given the prospects of weak consolidated earnings and elevated investment through 2022. On Feb. 9, 2021, S&P Global Ratings lowered its long-term local currency issuer credit rating on PTTEP to 'BBB+' from 'A-', following a similar action on PTT. At the same time, we affirmed our 'BBB+' long-term foreign currency issuer credit rating on PTTEP. We also affirmed our 'BBB+' long-term issue rating on the company's guaranteed U.S. dollar-denominated senior unsecured