Merrill Lynch & Co. have suspended a trader who had $400 million in undisclosed losses in the last few months, according to a report.

The Bank of America subsidiary, acquired at the start of the year, is looking closely into the case of Alexis Stefors, a currency trader in London. He was suspended after Norwegian and Swedish currency trades went wrong, people familiar with the situation told the Financial Times.

Merrill said yesterday it was in talks with regulators after reported discovering an “irregularity” in certain trading positions.

On Friday, the New York Times reported Stenfors was being investigated by British regulators. The report states he lost a substantial amount on his earnings.

Stenfors recorded a trading profit of $120 million in 2008, the Times said, citing people familiar with the matter.

Stenfors on Thursday called the matter a misunderstanding but would not elaborate.

The discovery was made a few weeks ago when Bank of America sent executives to investigate, the report stated.

The London discovery comes as New York’s top legal officer complained to the state’s top court on Friday that Bank of America is continuing to block his probe in to bonus compensation at the bank’s newly acquired Merrill Lynch division.

Cuomo is seeking a list of recipients of multi-million dollar bonuses awarded by Merrill Lynch. He claims large bonuses were “secretly and prematurely” awarded in December with Bank of America’s “apparent complicity.”