News reports said Singapore police seized the passports of two executives of China Aviation Oil (Singapore) Corp (CAO) in connection with CAO's US$550m in derivatives trading losses. Police said they were still waiting for suspended chief executive Chen Jiu lin to return to Singapore for questioning. Chen left with his wife for China last week, reportedly to attend to family business. CAO, China's biggest listed company in Singapore, is the mainland's monopoly importer of jet fuel. It is currently seeking court protection from creditors. The collapse is seen as the biggest bust since Singapore-based futures trader Nick Leeson broke Barings Bank.