The rating on Thai Oil Public Co. Ltd. (Thaioil) reflects the support the company receives from its operational integration with, and strategic importance to, state-owned oil and gas conglomerate PTT Public Co. Ltd. (PTT; BBB+/Stable/--). The rating also reflects Thaioil's favorable cost structure, flexibility in feedstock selection, and strong domestic market position. The company's financial ratios are somewhat better than we would expect for the rating. However, inherent industry risks and Thaioil's single-site and customer concentration risks partly offset these strengths. The company's credit protection measures continued to strengthen in the first half of 2011 because of higher refinery and aromatics margins. Better margins led to a 71% improvement in marketing gross integrated margins to US$8.9 per barrel for the
