Adding to an already tense environment, more problems became apparent in the mortgage market today. Countrywide Financial, the nation’s largest mortgage lender, said it had tapped $11.5 billion in emergency loans from 40 of the world’s largest banks, as it seeks to shore up its cash position.

The company, which relies heavily on raising money from Wall Street, acted a day after a prominent analyst suggested it may have to file for bankruptcy if banks and investors shut off the spigot of money to Countrywide. Shares of the company closed down 11 percent, after falling 13 percent yesterday. The stock is down more than 50 percent for the year.

In a statement released early this morning, the company also said that 90 percent of the home loans it will now make will be to standards set by Fannie Mae and Freddie Mac, the big purchasers of mortgage loans, because it is not able to sell them to other buyers.

The reversal of fortune in the housing market was further illustrated by figures released by the Commerce Department today that showed the rates of construction of new homes and building permits issued fell in July to their lowest levels in more than a decade.

A move by the Federal Reserve intended to calm the markets seemed to have little impact at first. The Fed injected $17 billion into the system this morning in two open-market actions by lending against mortgage securities.

Whether the turbulence in financial markets will have larger ramifications for the American economy is still unclear. Many economists, including those at the Fed, have said they believe the damage will remain contained. With each day of turmoil in the markets, however, the outlook becomes more and more murky.

Henry Paulson, the Treasury secretary, told The Wall Street Journal in an interview published today that market troubles “will extract a penalty” on economic growth, but he said he did not believe a recession was likely.