* Says requires a capital plan by May 19

* Can not assure that will be able to submit capital plan

* Says may not be able to return to profitability

May 18 (Reuters) - Struggling real-estate lender Corus Bankshares Inc CORS.O said it has to develop a capital plan by Tuesday, under its agreement with the Federal Reserve Bank of Chicago.

The bank can give no assurances that it will be able to submit an acceptable plan, including the required company guarantee, Corus said in a filing with the U.S. Securities and Exchange Commission.

The Chicago-based Corus, which has been posting losses for several quarters now, said it cannot assure that it will be able to resume profitable operations in the near future, or at all.

Earlier in the month, the company had said it was "undercapitalized" and that it was exploring strategic alternatives, including a possible sale.

The company, with over $7 billion in assets, had been put under special oversight by its primary federal regulators in February.

The lender has suffered from what it has called "a rapid and precipitous decline" in the value of collateral securing condominium construction loans, including many in hard-hit Arizona, southern California, southern Florida and Nevada.

Shares of Corus, which were trading as high as $10.58 in September, closed at 67 cents in regular session on Nasdaq Monday. (Reporting by Sweta Singh in Bangalore; Editing by Anil D'Silva)