Tell me more about Mitt Romney’s failures in the private sector again, Mr. President?

General Motors (GM) shares closed down 1.5% to 19.02 on Monday, hitting 18.85 intraday. That’s the lowest since the U.S. auto giant came public again in November 2010 at 33 a share. Update: GM shares early Tuesday fell 1.4% to 18.76, hitting a new low.)

That raises the taxpayer loss on the GM bailout to just shy of $35 billion. Here’s the math:

GM doesn’t have to pay back anything else, but taxpayers are still out $26.4 billion in direct aid. The Treasury still owns 26.5% of GM — 500 million shares. The stock would have to rise to about 53 to break-even on that direct aid. At the current price, the Treasury’s stake is worth just $9.51 billion. (Taxpayers lose $5 million for each penny that GM stock falls).

That would leave taxpayers out $16.9 billion. But the true cost is much higher.

President Obama let GM keep $45 billion worth in past losses to write off future earnings. These carry-forwards are typically wiped out or severely cut along with debts as part of bankruptcy. But in this case, the administration gifted huge tax breaks with an $18 billion book value. (That’s how GM avoided taxes last year despite a bumper $7.6 billion profit.)

Including those tax write-offs, taxpayers are sitting on a bailout loss of $35 billion.