Get your taxes done using TurboTax

With an employee stock purchase plan, the difference between what you pay for your stock and the fair market value when you purchase it is called the discount. That amount is reported as wage income on your W-2 form. When you sell the stock, the discount should be included in the amount you report for the cost basis of the stock. Often, your broker will not report a cost basis or will report only your cost as the cost basis and not include the discount. So, when you report the stock sale you may need to add the discount to the cost basis reported on the Form 1099-B.

A simple way to determine the cost basis of your employee stock shares sold is to divide the discount for the stock as reported on your W-2 form, plus any additional money you spent to acquire them, by the number of shares acquired. That will give you the cost of the shares that you can then multiply by the number of shares sold to arrive at their cost basis.

You need to edit your entry in the Investment Income section of TurboTax, then Stocks, cryptocurrency, Bonds, Mutual Funds, Other. Find the investment sale you need to edit in the Your Investment Sales summary and click on the Review tab:  

On the stock sale screen, indicate that the cost basis is missing or incorrect and you will have an opportunity to enter the correct cost basis.