Bill Ackman said ending Fannie Mae and Freddie Mac’s government conservatorship could create $500 billion in value, with 80% accruing to taxpayers; he called this a conservative estimate. According to Sina Finance, citing The Motley Fool and an interview transcript compiled by Stocktwits, Ackman made the remarks during Pershing Square’s third-quarter earnings call on Tuesday, November 3, and said the president could ring the New York Stock Exchange’s opening bell while creating hundreds of billions of dollars for taxpayers.

Pershing Square (NYSE: PS) holds about 10% of each company, and Ackman believes both stocks could rise tenfold. He called ending conservatorship a political necessity, saying the government has near-absolute authority over housing policy, mortgage terms, and loan underwriting under the current arrangement. He also said U.S. President Donald Trump could use an executive order to pursue the move even if the midterm election results are unfavorable to him.

The U.S. government has not announced an implementation plan. The U.S. Treasury holds senior preferred shares with a $238 billion liquidation preference, as well as warrants to acquire 80% of the companies’ common stock.