General Motors Corp. posted a company record $39 billion loss Wednesday for the third quarter, as a charge involving unused tax credits brought an abrupt end to a string of three profitable quarters for the nation’s largest automaker.

GM shares fell nearly 5 percent, or $1.67, to $34.48.

GM attributed most of the quarterly loss to a $38.6 billion noncash charge related to accumulated deferred tax credits in the U.S., Canada and Germany.

GM’s loss was the second-worst quarterly net loss in U.S. corporate history under generally accepted accounting principles, said Howard Silverblatt, senior index analyst for Standard & Poor’s. The loss was exceeded only by AOL Time Warner’s $44.9 billion loss in the fourth quarter of 2002, he said.