Mortgage-backed securities (MBS) are investment in mortgage loans. MBS issued by Government National Mortgage Association (GNMA or Ginnie Mae), Federal Home Loan Mortgage Corporation (FHLMC or Freddie Mac), and Federal National Mortgage Association (FNMA or Fannie Mae).More details here.
Government-Sponsored Enterprise (GSE)are privately held corporations created by U.S. Congress. GSEs carry the implicit backing of the U.S. Government, but they are not direct obligations of the U.S. Government. Examples of GSE: Federal Home Loan Bank, Federal Home Loan Mortgage Corporation (Freddie Mac), Federal Farm Credit Bank and the Resolution Funding Corporation.
Almost one and the same. The former are investment instruments and the later are corporations.