Investors & landlords

The cost basis could not be a negative number, so something must be wrong.

The cost basis of a restricted stock unit (RSU) would typically be the market price of the stock when it was vested, and that should have been reported on your W-2 form as wage income to you. If you included the value of the stock in your income upon vesting, then that would be the cost basis, which is often not reported on the form 1099-B.

You may be able to find the income reported on your W-2 or ask for a schedule from your employer.

When you enter your form 1099-B in TurboTax, you can list the cost basis as -0-, but then adjust it by clicking on the "I'll enter additional information on my own" box below the 1099-B entry screen. That will take you to a screen where you can enter the correct cost basis, and the difference will show up as an adjustment on your schedule D, capital gains and losses.