Stocks are considered employee compensation and your wife was taxed at the time of receipt of the stock award. You would report the fair market value of the stock at the time she received it as its cost basis.
How do you know that she was taxed on it when she received it? It should be reflected on her W-2 for that year. You may see an amount in Box 14 for stock awards. She may also find the information in her pay stubs for that year. If the 1099-B you received from your broker has $0 as the cost basis, it can be adjusted in TurboTax based on the value reported on her W-2. Please note that if the 1099-B reports the sale in a single transaction with "Various" as the acquisition date, you will have to break up the sales into separate transactions since they will have different cost bases.
@DavidM6
