Economists Forecast $600 Billion in QE3 Bonds

Will keep program going until unemployment hits 7 percent

The Federal Reserve will buy a total of $600 billion of bonds under its new stimulus program announced Thursday, known as QE3, and will look for a U.S. unemployment rate of 7 percent before it halts the program, according to the median of forecasts from a Reuters poll on Friday.

Forecasts from 52 economists for the ultimate size of the program ranged from $250 billion to $2 trillion, the poll found.

The Fed said on Thursday it was launching a new program of buying $40 billion a month of mortgage-backed securities bonds that would be open ended as it sought to "improve substantially" the outlook for the labor market.