WASHINGTON—Maurice R. Greenberg, American International Group Inc.'s former chief executive officer, has agreed to pay $15 million to settle civil charges related to alleged improper accounting transactions that inflated AIG's financial results, the U.S. Securities and Exchange Commission said Thursday.

In addition, Howard I. Smith, AIG's former chief financial officer, agreed to pay $1.5 million to settle similar charges.

The SEC Thursday announced the settlements and charges against the two former executives, which stemmed from a four-year investigation. Messrs. Greenberg and Smith, both of whom left AIG in 2005 amid probes into the New York-based insurer's accounting practices, agreed to settle the charges without admitting or denying the SEC's findings.

The federal regulators said the two former executives were responsible for “material misstatements that enabled AIG to create the false impression that the company consistently met or exceeded key earnings and growth targets.”

The SEC charged that Messrs. Greenberg and Smith are liable as “control persons” for AIG violations of securities laws. The charges, however, did not include fraud.

A statement issued by law firm Boies, Schiller & Flexner L.L.P., which represents Mr. Greenberg, said he was “pleased to finally put these issues behind him and be able to concentrate on building for the future.”

“Mr. Greenberg appreciates the SEC's recognition that he personally should not be charged with any fraud and the settlement is recognition of his lack of responsibility, even as a control person, for the vast majority of accounting issues included in AIG's restatement and the SEC's charges against the company,” the statement said.

The SEC said Messrs. Greenberg and Smith were involved in numerous improper accounting transactions that inflated AIG's earnings from 2000 to 2005, including a purported deal with an offshore shell entity to conceal multimillion-dollar underwriting losses from AIG's auto-warranty insurance business; a purported sale of tax-exempt municipal bonds owned by AIG subsidiaries to a trust that AIG controlled in order to improperly recognize capital gains; and “economically senseless” round-trip transactions to report improper gains in investment income, according to the SEC's complaint.

In addition, the complaint described two reinsurance transactions AIG entered into with a foreign subsidiary of Hartford Conn.-based General Reinsurance Corp. to allegedly falsely inflate its loss reserves and premiums written. These two key performance measures remained inflated in AIG's financial statements until its 2005 restatement, the SEC said.

In 2006 AIG agreed to pay $1.64 billion to settle fraud charges related to its practices, including its accounting, with state and federal authorities.

A spokesman for AIG declined to comment.

Mr. Greenberg is still fighting civil fraud charges from the New York attorney general's office related to the accounting probe.