Allen & Overy (A&O), Baker & McKenzie and Latham & Watkins have all taken roles on a $1bn (£636m) bond issuance by Thai Oil, one of the largest petroleum refineries in Thailand.

The publically-listed refining and petrochemical company, which is owned by Thailand’s PTT Group, issued a dual tranche of senior unsecured fixed-rate notes to foreign institutional investors earlier this month.