A U.S. commission is planning to focus on the ties between Goldman Sachs Group Inc and American International Group Inc, and how derivatives transactions between the two financial giants may have contributed to the financial crisis.

The Financial Crisis Inquiry Commission, a congressionally appointed panel, will begin two days of hearings on Wednesday headlined by former AIG Financial Products head Joseph Cassano and Goldman President Gary Cohn.

A key focus on the hearing will be how the interaction of these two financial giants may or may not have contributed to the causes of the financial crisis, Phil Angelides, chairman of the commission, said in a call with reporters on Tuesday.

Goldman has long been criticized for benefiting from the U.S. taxpayers' bailout of AIG. Taxpayers pledged up to $182 billion to address problems at AIG's financial products division.

U.S. and European banks that had purchased credit protection from AIG were quickly made whole after the U.S. government bailed out AIG. Goldman, as a major trading partner of the insurer, was one of the biggest beneficiaries of the government rescue of AIG.

Cassano, who has evaded public appearances since leaving the bailed-out insurer more than two years ago, participated in more than five hours of preliminary interviews with the commission's staff, Angelides and vice chairman Bill Thomas said.

He was at the center of this. He obviously knows a lot about not just what they did, but the interrelationship with Goldman Sachs, Angelides said.

The commission said that a raft of Goldman executives, including Chief Executive Lloyd Blankfein, also participated in preliminary interviews for the derivatives-focused hearing. Blankfein, who testified before the commission in January, is not scheduled to participate in this week's hearings.

Among those expected to appear are Goldman Chief Financial Officer David Viniar, former AIG Chief Executive Martin Sullivan, and AIG Chief Risk Officer Robert Lewis.

The FCIC has been holding both public hearings and private meetings with financial industry players, including investor Warren Buffett, to piece together the causes and impact of the financial meltdown.

The commission is supposed to issue a report by December 15, detailing the crisis that peaked in late 2008 after the collapse of former investment banking giant Lehman Brothers.

The report will serve as a public record of the historic event and will not likely include thorough recommendations for reform.

(Reporting by Steve Eder, Karey Wutkowski, and Kim Dixon in Washington; Editing by Tim Dobbyn)

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