Wall Street recovered nearly 190 points after Standard & Poor's affirmed its ratings for Ambac Financial Group Inc. and MBIA Inc., raising hopes that troubled bond insurers will emerge from the credit market crisis on solid footing.

An analysis of the Bear Case against MBIA by William Ackman.

MBIA Inc. reported write-downs of $3.5 billion on souring credit markets Thursday, exacerbating concerns that rising costs could squeeze local governments as well as slow any recovery for big banks.