Some officials believe the offering could raise around $30 billion and value the combined firms at roughly $500 billion or more.

U.S. President Donald Trump's administration could kick off initial public offerings of Fannie Mae and Freddie Mac later this year, according to a senior administration official, marking a key milestone for the mortgage finance giants that have been under government control for years.

The Trump administration is reportedly looking to sell stock in Freddie Mac and Fannie Mae, which could be valued at roughly $500 billion.