The U.S. Treasury Department unveiled its plan today to buy up to $1 trillion of mortgage securities, whose collapse in value helped trigger the recession.

The news brought a positive response from the stock market. At 11:26 a.m. Iowa time, the Dow Jones industrial average was up 4.24 percent, with financial stocks showing the biggest gains.

Under the department’s Public-Private Investment Program, taxpayer funds will be used to seed partnerships with private investors that will buy toxic assets backed by mortgages and other loans, CNNMoney.com reported.

The program will receive a jump-start of $75 billion to $100 billion from the department’s remaining bank-rescue funds. The goal is to buy at least $500 billion of existing assets and loans, such as subprime mortgages that are now in danger of default.

The Treasury Department said in a news release that the program could potentially expand to $1 trillion over time. The government hopes that the program will help cleanse the balance sheets of many of the nation’s largest banks, which continue to suffer billions of dollars in losses, and help get credit flowing again.

Because the program depends on private investors stepping up, it may be weeks or months before it’s clear whether the approach will work.

“You will start to see this buying up the assets” shortly after private asset managers are chosen by May, Austan Goolsbee, a member of the White House Council of Economic Advisers, told Bloomberg Television.

“There is no doubt the government is taking risk. You cannot solve a financial crisis without the government assuming risk,” Treasury Secretary Timothy Geithner told reporters at a news conference in Washington, D.C.