The chairman of the House Oversight and Government Reform Committee announced late this week that he has opened an investigation into a reported deal struck last month in which Fannie Mae agreed to buy some of Bank of America’s home-loan portfolio.In a letter sent to Federal Housing Finance Agency Acting Director Edward DeMarco, Rep. Darrell Issa, R-CA, requested the FHFA provide the committee documents and a “full explanation of the agency’s decision-making process” regarding the purchase.