NEW YORK, Nov 18 (Reuters) - Pershing Square Capital

Management founder Bill Ackman said on Tuesday that proposals to

sell a piece of the U.S. mortgage agencies Fannie Mae and

Freddie Mac in an initial public offering is not possible in the

short term.

The U.S. government, which has been controlling the enterprises

for 17 years, has been considering different structures for a

potential IPO, including the creation of a single company

representing both of them, but the complexity of such a deal has

been a hurdle.

"The sale of a piece of these companies to the public is

neither feasible nor desirable at this moment," Ackman said

during a presentation posted on X on Tuesday. Both companies are

already listed in the over-the-counter market.

U.S. President Donald Trump's administration is

"opportunistically evaluating" such an IPO, possibly as soon as

the end of 2025, Federal Housing Finance Agency Director William

Pulte

said

last month. Trump

held meetings with bank CEOs

to discuss this as a way to end the U.S. conservatorship of

the enterprises, which began in 2008 after they suffered heavy

losses during the subprime mortgage crisis.

Ackman, whose fund owns stakes in Fannie Mae and Freddie Mac,

has benefited as their share prices have risen since the

government began considering a privatization.

Ackman proposed instead that these enterprises simply convert

their listings currently on the over-the-counter market to the

New York Stock Exchange, a process he estimated could take a few

weeks.

This could result in valuations close to $400 billion for the

two, he said, noting that the government's stakes would be worth

around $300 billion and could be sold off.

The billionaire also suggested other steps needed to list

the companies, such as recognizing previous payments made by the

agencies as repayment of the senior preferred stock issued

during the crisis. Then the U.S. Treasury would exercise

warrants it got during the crisis to reach a 79.9% common stock

stake. Ackman also proposed lowering the current capital

requirement of 4.5% of all guarantees.

Merging Fannie Mae and Freddie Mac into a single company for a

listing is out of the question, since it would require

congressional approval, three sources with knowledge of the

matter said in the past two weeks, asking for anonymity to

discuss private talks.

Creating a holding company would be a simple way to sell

stakes, but government entities are not allowed to create

vehicles for this strategy, one of the sources said. An

extremely complex option is to use an existing joint venture

between Fannie Mae and Freddie Mac as a listing vehicle and

transfer assets to it.