The Treasury has administrative options for addressing the status of bailed-out mortgage giants Fannie Mae and Freddie Mac if Congress fails to act, Treasury Secretary Steven Mnuchin said Tuesday.

Mnuchin told lawmakers at a Senate Banking Committee hearing that his "strong preference" would be for Congress to overhaul the two government-sponsored enterprises through bipartisan legislation. But he also noted that the Trump administration could act if Congress does not.

"There are certain administrative options that we have," he said.

Mnuchin declined to specify what those alternatives might be, though, saying that his comments could rile markets.

His responses came in questioning with Sen. Bob Corker, R-Tenn., a senior member of the panel working toward bipartisan legislation to overhaul the housing finance system and resolve the bailed-out status of Fannie and Freddie.

The two companies were taken over by the government during the 2008 financial crisis and have remained in conservatorship since. The Treasury owns senior preferred stock in the two and has warrants representing a majority owner stake in each. Private investors, though, still own shares in the companies.

Legislation authored by Corker in 2015 prevented the Treasury from selling its stake in Fannie and Freddie for two years. That provision expired as 2018 began. The purpose of the bill, he said at the time, was to prevent the government-sponsored enterprises from returning to the model of private profits and subsidized losses that prevailed prior to their 2008 bailouts.

The Obama Treasury ruled out the possibility of administrative action on Fannie and Freddie.

Mnuchin said Tuesday that he was open-minded in working with Congress on reform legislation, but that he supported maintaining some kind of a government backstop for mortgage-backed securities to ensure that the 30-year fixed-rate mortgage remains widely available. Fannie and Freddie, which are fully backed by the federal government, currently provide that backstop.

"I think it’s critical that we have a 30-year mortgage," Mnuchin said. "I don’t believe that private markets on their own could support it."