NEW YORK (CNNMoney.com) -- Freddie Mac asked for another $6.1 billion in government aid Tuesday, after reporting a $9.9 billion quarterly loss.

Including the most recent request, Freddie Mac (FRE, Fortune 500) has drawn $51.7 billion of its $200 billion lifeline from the Treasury Department. Last quarter, when it reported a loss of $23.9 billion, the company asked the government for $30.8 billion.

Quarterly results at the troubled mortgage finance company, which was taken over by the federal government in September, were dragged down by rising credit losses and writedowns on the deteriorating value of its mortgage-backed securities.

"This was another difficult quarter for Freddie Mac, as declining home prices and the weak economy continued to take a toll on our results," said Freddie Mac Interim Chief Executive John Koskinen.

"While we expect coming quarters to be difficult, we are seeing preliminary signs of slowing in home price declines as low mortgage rates and high affordability take hold, and conforming mortgage credit to prime borrowers continues to be widely available," he said.

Its loss came to $3.14 per share, up from $0.66 per share a year ago, when its net loss was $149 million.

On Friday, sister company Fannie Mae reported a first-quarter loss of $23.2 billion, or $4.09 a share, and said it was requesting $19 billion in additional aid.

Rough quarter

Freddie Mac has had a difficult time in recent months. David Moffett, whom the federal government appointed to oversee the finance company, resigned in March but returned a month later as a consultant after Freddie Mac's acting chief financial officer David Kellermann died from an apparent suicide.

With its delinquency rates rising to 2.29% in its single-family loan portfolio from 0.77% a year ago, Freddie increased its provision for credit losses to $8.8 billion, up from $1.2 billion a year ago.

It took a writedown of $7.1 billion on its mortgage-backed security portfolio.

The company benefited from lower funding costs, allowing it to record net interest income of $3.9 billion, up from $2.6 billion a quarter ago. It also recognized gains of $3.8 billion on its derivative portfolio.

More loan modifications

The Obama administration is leaning heavily on Freddie Mac and Fannie Mae (FNM, Fortune 500) to help struggling homeowners and lift the housing market out of its crisis. Freddie implemented on March 4 the administration's refinancing program, which allows homeowners with little or no equity to refinance, and its loan modification initiative, which lets eligible borrowers lower their monthly payments to 31% of pre-tax income.

The company modified more than 24,620 loans in the first quarter, up from 17,700 in the previous quarter and 4,250 a year ago. It also put nearly 10,500 troubled borrowers into repayment plans and entered into 1,850 forbearance agreements and 3,100 pre-foreclosure sales.

It also purchased or guaranteed $148 billion in mortgage loans and mortgage securities, financing more than 500,000 single-family homes and 70,000 units of rental housing. Its single-family refinancing purchase volume surged to about $95 billion, nearly quadruple the previous period's, thanks to super-low mortgage rates.