The Securities and Exchange Commission’s enforcement chief assured a congressional panel Friday that his agency has widened its investigation into Bank of America and is examining “all aspects” of its controversial January merger with Merrill Lynch & Co., Inc., including Merrill’s spiraling fourth-quarter losses last year.

Enforcement director Robert Khuzami testified about the SEC’s probe before the House Committee on Oversight and Government Reform. Rep. Dennis Kucinich, D-Ohio, pressed Khuzami on the $15.3 billion in fourth quarter losses, saying the committee has discovered evidence that BofA executives and lawyers knew or should have known about the potential losses in time to disclose them to shareholders before a vote on the merger.