NEW YORK (MarketWatch) -- Ken Lewis, chairman and chief executive of Bank of America Corp. has been subpoenaed by New York State Attorney General Andrew Cuomo, according to a report published Friday.

Cuomo is looking into whether Bank of America BAC, -1.32% withheld information from investors in relation to its purchase of Merrill Lynch & Co., said The Wall Street Journal.

Cuomo is investigating whether investors were misled about the depth of Merrill's losses in late 2008, said the Journal.

Bank of America agreed to buy Merrill in mid-September, as doubts swirled about Merrill's viability.

Investigators also took testimony from John Thain, the former Merrill CEO, on Thursday. The Journal said Thain was in particular quizzed on why the September agreement contained a nonpublic attachment that detailed the maximum Merrill could pay in bonuses.

The paper cites a person close to the matter, who claims that regulators are eyeing Lewis' congressional testimony earlier this month when he said he had no authority over the bonuses.

Cuomo's team is looking into how Merrill could have set the bonuses, and told staff about them, before the end of the quarter. They are also probing whether trading losses were adequately disclosed to shareholders and boards of Bank of America and Merrill, and what top executives who approved the bonuses knew about the losses.

While Bank of America's acquisition of Merrill was hailed at the time the deal was announced, Merrill's fourth-quarter losses of more than $15 billion, revealed the extent of the troubles that Bank of America had taken on. It was forced to ask for billions of additional government money to help seal the deal.

The difficulties in closing the acquisitions reportedly led to tensions between Lewis and Thain, with the latter resigning in late January. See full story.

Since Thain's resignation, there have been conflicting reports about how much Bank of America executives knew about Merrill's problems, including the bonus awards, before they were publicly revealed.