Freddie Mac and Fannie Mae reportedly face being put under federal government control in an attempt to rescue them.
Media reports say the heads of the two mortgage agencies would be removed under the US Treasury plans - which could see the largest ever financial bail-out in the United States.
The two companies, which are mandated to provide funding to the US housing market, hold or guarantee half the country's mortgage debt.
In July, Congress approved a plan aimed at offering them more liquidity.
This followed huge losses by the two firms as result of a big increase in defaults and repossessions in the US housing market.
Citing senior administration sources, The Washington Post said the firms would be put under a legal status known as "conservatorship" which would greatly reduce the value of the two companies' common stock.
Other securities - including company debt and preferred shares - would be guaranteed by the government.
The New York Times reported that senior executives at Freddie Mac and Fannie Mae were informed about the plan on Friday.
The Wall Street Journal said it would include changes in the top management.
The papers say there would also be quarterly infusions of cash to keep both firms afloat. The total cost to taxpayers is not known but could amount to billions of dollars.
In the past year, the financial crisis have taken a heavy toll on both Fannie Mae and Freddie Mac: they lost a combined $US3.1 billion between April and June.
Together, they own or guarantee about $US5.3 trillion worth of home loans - about half the outstanding mortgages in the US.
