PTT Oil and Retail Business is a unit of state-owned oil and gas giant PTT Pcl and its shares reached nearly 27 baht, or 50% above the top-end of its IPO price of 18 baht, compared with an overall 0.7% decline in the index.
"Shares were oversubscribed by many times and above expectations... with over 530,000 retail investors," chief executive Jiraporn Kaosawad said at an event at the Stock Exchange of Thailand.
PTT remained the company's largest shareholder with 74.16% of shares, stock exchange data shows.
The long-planned IPO comes after some blockbuster listings in 2020, with Central Retail Corporation Pcl and SCG Packaging Pcl each raising over $1 billion.
The company, which operates gas stations and Cafe Amazon coffee shops, said it would use proceeds from the offering to expand network fuel stations and its commercial business.
(This story corrects to add dropped words in company name, "PTT Oil and Retail Business" not "PTT Retail Business")
(Reporting by Chayut Setboonsarng; Editing by Ed Davies)