House Oversight Committee Chairman Darrell Issa (R-Calif.) is wondering why Fannie Mae agreed to buy 400,000 mortgages from Bank of America and whether its purchase of the risky assets constitutes a "backdoor bailout" of the bank. Issa sent a letter Thursday to Edward DeMarco, the acting director of the Federal Housing Finance Agency (FHFA) that regulates Fannie, asking for a justification of the deal, especially in light of the bank's recently announced spate of layoffs. "The transaction appears to have shifted a significant amount of risk from BofA's portfolio to Fannie.