Mortgage Pool Daniel Guidotti 14 years ago Mortgage PoolCollection of mortgages used as collateral and held in trust for issuing a mortgage-backed security. MBSs issued by Fannie Mae, Freddie Mac and Ginnie Mae are the simplest form of such security and are pools themselves.Recommended for you:Mortgage Pass-Through Security Mortgage-Backed Securities Clearing Corporation Delayed Issuance Pool Grantor Trust