In 1970, to compete with Fannie Mae in the secondary market, another GSE was created – the Federal Home Loan Mortgage Corporation, or Freddie Mac. Also in 1970, Ginnie Mae issued the first mortgage passthrough security, followed soon after by Freddie Mac.
In the early 1980s, Freddie Mac introduced collateralized mortgage obligations (CMOs), which separated the payments from a pooled set of mortgages into "strips" carrying different effective maturities and credit risks. Since 1980, the outstanding volume of GSE mortgage-backed securities has risen from less than $ billion to more than $ trillion today.