Freddie Mac on Wednesday posted a second-quarter loss more than three-times larger than Wall Street expected as more homeowners fell behind on their mortgages.

The loss comes just weeks after the government threw a financial lifeline to Freddie and its sister company Fannie Mae to ward off fears the pair could collapse and take down the U.S. mortgage market. Together, the two hold or guarantee nearly half of outstanding U.S. mortgage debt.

In a troubling sign that mortgage delinquencies and foreclosures are increasing, Freddie set aside $2.5 billion -- more than double what it had reserved in the first quarter.

Freddie Mac Chief Financial Officer Buddy Piszel told The Associated Press that the credit problems are emerging mostly in the company's Alt-A portfolio, which contains mortgages with high risk factors like undocumented borrower income.

Alt-A loans make up 10 percent, or $190 billion, of Freddie's entire portfolio. The percentage of those mortgages that were more than 90-days past due rose to 3.72 percent from 2.32 percent in the first quarter.

For all of Freddie Mac's loans, the percentage of seriously delinquent loans edged up to 0.82 percent from 0.74 percent.

To preserve capital, the government-sponsored company said it expects to cut its dividend this quarter to 5 cents or less a share from 25 cents a share.

The McLean, Va.-based company also said it would sell at least $5.5 billion in stock.

On Tuesday, the Treasury Department said it retained investment firm Morgan Stanley to help the government assess the state of the mortgage market and give a financial profile of Fannie and Freddie.

Also on Tuesday, Fannie Mae said it will double the fee it charges lenders and brokers to help it gird against higher credit risks and losses from mortgages it buys from lenders.

Piszel said Freddie is evaluating its pricing, but isn't announcing any action now.

Fannie Mae reports its quarterly financial results Friday.