Fitch Ratings (Thailand) has placed an AAA(tha) national long-term rating on PTT's (BKK:PTT) upcoming 40 billion baht medium-term debenture program, according to a Monday release.

The senior unsecured debentures in the program will have the same rating as the issuer's national long-term rating since they serve as its obligations, Fitch said.

The rating agency considers "very strong" incentives to support from the Thai government, given the company's main role in the country's energy security.

A default could result in impeded oil and gas availability in the country, which will hit electricity generation and weaken energy security, Fitch said.

The state owns a 63% stake in the company, reflecting "strong" responsibility to support, according to Fitch.

The company exhibits moderating but solid earnings, elevated capital expenditure, and a robust financial position.

Changes in Thailand's ratings could trigger similar actions on the issuer, while sustained erosion in its EBITDA net leverage to above 2.5x and negative regulatory changes could impact its standalone credit profile, Fitch said.