The attorney-general of New York has issued subpoenas to seven executives of Merrill Lynch, each of whom got a bonus over $10 million for 2008, requiring them to make legal statements, the Financial Times has reported.

The bonuses were contoversial because Merrill reported $15.8 billion in losses for the fourth quarter and $27.6 billion for the full year, and Bank of America - about to acquire Merrill Lynch - had just asked the US government for $20 billion to complete the transaction.

According to the paper's unnamed source, the authorities want to know when the executives found out what their bonuses would be and who informed them.

Bonus payments to banking executives have become a hot political issue in the US and Europe as a number of financial institutions have been bailed out with taxpayers' money.