WASHINGTON — Two former top executives of Fannie Mae were to face questions today about the government-created mortgage titan's role in fomenting the housing boom and its eventual bust.

Daniel Mudd, Fannie Mae's chief executive during the housing boom, and Robert Levin, the company's former chief business officer, are due to appear in the third day of hearings examining the roots of the financial crisis.

Both executives left Fannie Mae after it was seized by regulators in fall 2008. Also scheduled to appear are James Lockhart and Armando Falcon, both of whom headed up the federal regulator for Fannie Mae and Freddie Mac.

The inquiry is being held by the congressionally chartered Financial Crisis Inquiry Commission, which Congress created last year to examine the causes of the crisis. The panel's goal is to get an in-depth understanding of decisions.