Key to the jump was a writeoff that was part of a financing package to keep automaker Chrysler afloat during the recession.
Report to Congress says loss is up from a previous estimate of $10.5 billion.
Dan Akerson says taxpayers would have had to pick up the company’s $26 billion pension obligation if the automaker went under.
Federal, state governments also would have lost $39.4 billion in tax revenue and other payments
The Canadian government sold a block of 30 million GM shares in September, valued at $1.1 billion.
Watchdog report says “no question” taxpayers are going to lose money on the investment.