PTSC AP, established in 2012, is a joint venture between PTSC and Yinson Holdings Berhad (YINSON) to invest and supply FPSO PTSC Lam Son to Lam Son Joint Operating Company (Lam Son JOC) for the operation in Thang Long–Dong Do fields, Blocks 01/97 & 02/97 offshore Vietnam, contract starting since June 2014.