Capital requirements regarding bank holdings of non-agency MBS increased significantly after federal regulators implemented Basel III reforms in 2014. And while banks have largely been reluctant to re-enter the market for non-agency MBS issuance, a recent report by the Government Accountability Office suggests that the impact of bank involvement in the non-agency MBS market is unclear. The GAO was asked to explain how capital requirements for a mortgage depend on how the loan is financed and how the requirements have changed since the financial crisis. The report was requested by Sen. Richard Shelby, R-AL, who until recently was the chairman of the Senate Committee on Banking, Housing and Urban Affairs. The GAO noted...