Chen Jiulin left Singapore after the company announced last week that it had lost US$550 million on derivatives trading, forcing it to seek court protection from creditors.

A company spokesman said Monday Chen had agreed to return to face investigators.

He later was released on bail, authorities said. No charges have been filed.

Earlier Wednesday, the Singapore Stock Exchange said the parent company had expressed regret over the massive losses of its jet fuel supplier.

Late Wednesday, Chen left the office of the Commercial Affairs Department, Singapore’s white-collar crime unit, briefly telling reporters that he had returned to help in the investigation.

China Aviation Oil spokesman Gerald Woon said company officials were cooperating fully with criminal investigators, and that four other senior officers had voluntarily surrendered their passports.

China Aviation Oil Corp. supplies most of the jet fuel used in China. It is based in Singapore, a major oil-trading center, but majority-owned by China’s State-owned China Aviation Oil Holding Co.

Derivatives dealings allow companies to hedge against risks from price fluctuations by agreeing in advance to buy or sell goods at some future date. They can bring huge gains, but they also carry great risks. Enditem