Shares of the company plummeted 26 percent in early trading, to $27.83.

“Without doubt, 2007 has been an extremely difficult year for the country’s housing and credit markets,” Richard F. Syron, the chairman and chief executive of Freddie Mac, wrote in a statement.

Mr. Syron was not alone in his lament. D. R. Horton, the nation’s largest home builder, reported a $50.1 million loss in its fiscal fourth quarter as the housing downturn pummeled its inventory, goodwill and land-use contracts. Lower demand and tighter lending standards have cut back the company’s business and caused many clients to cancel contracts.

“We expect the housing environment to remain challenging,” Donald R. Horton, the company’s chairman, said in a statement.

The subprime debacle also claimed another high-profile casualty: H&R Block’s chairman and chief executive, Mark Ernst, who said today he would resign amid the company’s exposure to risky loans. Richard C. Breeden, the former chairman of the Securities and Exchange Commission, will take over as chairman. The chief executive slot will be temporarily filled by Alan M. Bennett, a former top executive at Aetna, the insurance company.

Home building data released by the government today suggested the troubles in the housing sector will continue. Permits for residential groundbreakings fell 6.6 percent in October to their lowest level in over 14 years. They have dipped nearly 25 percent since last October, to a seasonally adjusted 1.18 million annual rate, the Commerce Department said.

Meanwhile, new residential construction grew slightly last month, rising 3 percent, to a 1.23 million annual pace. It was the first increase in four months, but housing starts remain near the lowest level since the recession of the early 1990s.

Investors will also be focusing on today’s economic forecast from the Federal Reserve. Central bankers have warned that housing problems will continue unabated into next year.