Mortgage pools are a group of mortgages used as collateral for a mortgage-backed security. These pools are held in special purpose vehicles, which allow an originator to move mortgages off its balance sheet into a bankruptcy-remote vehicle.
Agency- and GSE-backed mortgage pools include mortgage pools backed by four types of properties: (1) pools consisting of one to four-family mortgages, issued by the Government National Mortgage Association (Ginnie Mae), the Federal National Mortgage Association (Fannie Mae), and the Federal Home Loan Mortgage Corporation (Freddie Mac); (2) pools of multifamily loans issued by Ginnie Mae, Fannie Mae, and Freddie Mac; (3) pools of commercial mortgages issued by the Farmers Home Administration (FmHA), which wound down all of its commercial mortgage pools at the end of 1996 (FmHA also formed one to four-family, multifamily, and farm mortgage pools, but withdrew completely from that business by the end of the 1990s); and (4) pools of farm mortgages issued by the Federal Agricultural Mortgage Corporation (Farmer Mac).
Securities issued by the agencies to fund these pools are known as mortgage-pool securities. These obligations are largely pass-through securities, in which purchasers receive interest, amortization, and principal payments on the underlying mortgages. In the financial accounts, these securities are part of the instrument category of agency- and GSE-backed securities and are equal to the unpaid balances of the mortgages in the pools.
Note: Beginning in the first quarter of 2010, Freddie Mac and Fannie Mae moved almost all of their one to four-family mortgage pools on to their consolidated balance sheets in response to new accounting rules (Financial Accounting Standards Nos. 166 and 167). Some multifamily pools issued by those GSEs also were moved on to their balance sheets, as well as some pools of farm loans issued by Farmer Mac.