The Federal Home Loan Mortgage Corp. yesterday announced that it has suffered $124 million in loan losses in the last three months because more owners of homes and apartment buildings have defaulted on their mortgages.

The Reston-based financial company, widely known as Freddie Mac, said deteriorating economic conditions in New York City and Atlanta, two markets in which it owns a total of about $2 billion worth of apartment building loans, were an important factor in the firm's worsening loan loss picture.

The third-quarter defaults bring to $229 million the amount the company has written off this year as a result of escalating mortgage defaults, but the company said it has already set aside $522 million to cover defaults. President Leland Brendsel, in a statement, said Freddie Mac will still post a third-quarter profit when results are released later this month.

On Wall Street, trading in Freddie Mac stock was halted before the announcement of the loan losses. When it resumed, it shares dropped $1.87 1/2 to close at $37.87 1/2 in active trading.

Earlier this month, Freddie Mac ceased paying cash for mortgages for apartment buildings and town house complexes -- a decision that is expected to make it much more difficult for owners and buyers of small apartment buildings to obtain loans.

The company also reported problems in its single-family programs. While multifamily housing accounted for $81 million of the $124 million in losses, the rest, $43 million, resulted from defaults on single-family home loans.

Some $16.4 million of the single-family losses resulted from two large mortgage fraud schemes, one costing the company $11 million and the other $5.4 million. Officials refused to provide any details of the schemes, saying that more information will be made available when third-quarter earnings are released at the end of this month.

Multifamily mortgages make up only 3.2 percent -- $11 billion -- of the $322 billion in housing loans owned by Freddie Mac, but account for about 50 percent of its losses. Over the past 18 months, the company has lost more than $200 million on multifamily loans.

Some $400 million of Freddie Mac's multifamily loans are either in foreclosure or at least 60 days delinquent. The firm said that if all of the $400 million goes through foreclosure, and if the loss experience mirrors that of Texas during the 1980s, the company could lose up to $240 million -- a figure still well below its $522 million reserve.

Robert Quinlan, Freddie Mac's senior vice president, said that is "a worst-case scenario" and the company does not expect that to happen. But he added that the bulk of the losses, whatever they are, will become known during the fourth quarter of the year.

"We wanted to make a full disclosure to the marketplace," he said.

Freddie Mac is a congressionally chartered, privately owned corporation that buys mortgage loans from banks, thrifts and mortgage bankers, allowing them to turn around and relend the money again.

In most cases, Freddie Mac assembles its loans into packages and issues securities against them to investors, to whom the mortgage payments are eventually passed.

When any mortgage holder defaults on a loan, Freddie Mac forecloses on the property, making up any loss to investors who hold the securities.

The announcement by Freddie Mac is the latest jolt to the financial services industry as property values decline in many regions, affecting the performance of banks, savings and loans, mortgage bankers and insurance companies.