Detroit ? General Motors Corp.’s disclosures that it lost $2 billion more last year than previously reported and needs more time to sort out accounting errors in the finance business it wants to sell gave investors fresh reasons to worry about the world’s biggest automaker. They sent GM’s shares price down nearly 5 percent Friday, shaving more than a half-billion dollars off its market value.

GM said after the market closed Thursday that it now estimates it lost about $10.6 billion in 2005 compared with its preliminary report of a loss of $8.6 billion.