Where do you report "income" from vested restricted stock options (RSU) if you consult on the side for a startup (that doesn't issue you a W-2). Under schedule C?

"Under schedule C?"

Yes.  It's part of the line 1 "revenue" figure on Schedule C, reported at the stock's FMV at the date of vesting.  Obviously you report this a form of "general" income, i.e., not reported on a 1099-MISC.

If and when you sell the stock, that's when the 1099-B comes into play.  The stocks basis is the same as the revenue reported.

Tom Young

If you have RSU sales to report, this is a type of investment income that does not get reported on a Schedule C. You should have gotten a 1099-B tax form for these sales. If you didn't get a W-2 or had taxes withheld on the RSU sale, you may owe taxes. 

To enter this income in TurboTax, go to Federal Taxes, Wages & Income, and find the Investment Income section and Start the Stocks, Mutual Funds, Bonds, Other topic.