Clifford Chance has advised Thai oil and gas giant PTT Exploration and Production Public Company Limited (PTTEP) on its $1 billion corporate hybrid bond offering, the first Thai corporate issue in the U.S. dollar hybrid securities market.

Allen & Overy acted for joint bookrunners Bank of America Merrill Lynch, Credit Suisse, HSBC and JPMorgan.

According to the Thomson Reuters publication IFR, the rare hybrid bond is one of the various forms of financing being used by PTTEP to pay for its $2.2 billion acquisition of Cove Energy PLC and to fund capital expenditure. PTTEP became Thailand’s first corporate issuer of a perpetual bond, the only previous ones having come from the financial sector, namely Krung Thai Bank and TMB Bank.

The Clifford Chance team was led by partners Crawford Brickley and Matthew Fairclough, while the Allen & Overy team was led by partners Alex Stathopoulos, John Lee and Suparerk Auychai.

PTTEP is Thailand’s largest exploration and production company of oil and natural gas, and is the third-largest publicly listed company on the Stock Exchange of Thailand. PTTEP operates more than 40 projects around the world.