Guaranty Financial Group Inc. in Austin has a May 21 deadline to raise capital or start looking for a buyer.
In a Securities and Exchange Commission filing Wednesday, the $15 billion-asset Guaranty disclosed that it received a cease-and-desist order from the Office of Thrift Supervision on Monday.
The company said that it must raise "substantial" capital to comply with the order and that it is trying to do so.
The order gives Guaranty's thrift unit until May 21 to achieve a core capital ratio of at least 8% and a total risk-based capital ratio of 11%. If it fails, it must adopt a plan to sell or liquidate itself.
Guaranty said that it believes the thrift is below those levels now.
The company has yet to file its fourth-quarter and annual results because, it said, it is working with regulators to determine how much of a writedown it must take on its mortgage-backed securities portfolio.
Guaranty, which has been suffering from a surge in nonperforming assets, has not reported a quarterly profit since it was spun off from the Austin conglomerate Temple-Inland Inc. in late 2007.
Last summer the company raised $600 million from prominent investors, including Carl Icahn and Robert Rowling.
But observers have said that Guaranty is likely to have trouble getting another infusion.