Washington Mutual

(WM) - Get Report

shares were falling 18.6% Monday morning after the

Wall Street Journal

reported that the nation's largest thrift is being pressured by regulators to either sell itself or recapitalize.

Last week the Seattle-based company had been reported to put itself on the auction block, with suitors such as

Citigroup

(C) - Get Report

,

JPMorgan Chase

(JPM) - Get Report

,

Wells Fargo

(WFC) - Get Report

and

Banco Santander

(STD)

considering a deal, reports say.

Washington Mutual

has been the source of much speculation of late regarding a sale, but so far no agreement has emerged.

A sale may go faster if the deal was structured as a government-assisted takeover, the

Journal

says. In one scenario, the Federal Deposit Insurance Corp. would take control of WaMu's banking operations and then sell its deposits to another bank, the

Journal

says.

WaMu executives are also considering raising additional capital, the article says. The company raised more than $7 billion in April from an investor consortium led by private equity firm TPG, which recently waived a provision in its investment agreement requiring WaMu to pay the firm back for any significant dilution it would feel if the company decided to raise more capital or sell itself.

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Wachovia

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, a major stumbling block for a sale is WaMu's exposure to troubled mortgages and, increasingly, to credit card defaults. The company has said that it expects cumulative losses on its assets to reach $19 billion but some analysts say it could go higher.

WaMu shares were down 79 cents to $3.46.