The Securities and Exchange Commission (search) has sent subpoenas to as many as 12 executives at American International Group Inc. (AIG) amid several probes into whether questionable transactions were used to improperly bolster AIG's financial standing, The Wall Street Journal reported in Monday's editions.

Meanwhile, the Journal, citing unidentified sources familiar with the case, said the AIG board overseeing an internal probe of the transactions could decide in the next few days whether to formally sever ties with Chairman Maurice R. "Hank" Greenberg (search).

Greenberg, 79, was replaced as chief executive two weeks ago — though retained as chairman — as regulatory scrutiny mounted over a 2000 transaction that appeared to have been used to boost the company's reserves artificially. He had been at the company's helm for four decades.

Greenberg has since become frustrated that he may be chairman in name only, and could pre-empt any board action by retiring, the Journal said, citing a source. Through his lawyer, he declined to comment.

Greenberg is scheduled to give a deposition to New York Attorney General Eliot Spitzer (search) on April 12. Should he refuse to testify, directors could force him out, as they recently did two other executives, including Chief Financial Officer Howard I. Smith, who refused to cooperate with investigators.

On Sunday, the company forced out another longtime executive, Michael Murphy, a confidante of Greenberg and an expert of tax matters who is based in Bermuda, the Journal reported citing unidentified sources. Murphy's attorney, Sean O'Shea, said Sunday that he had not been informed of his client's dismissal, and did not know whether Murphy had been notified.

AIG continues to "believe that the matters subject to review are unlikely to result in significant changes to the company's financial position," meaning shareholder's equity, said an AIG spokesman, Chris Winans.