When you enter the loss for the worthless stock you can use the following steps to enter your loss and label it as such.
This is reported like a stock sale without a Form 1099-B
1. Sign into your TurboTax account (online or desktop)
2. Use the search box in the upper right
3. Search for investment sales
4. Jump to investment sales (see attached image)
5. Make the selection for the type of investment
6. Continue to enter your transaction using "Worthless" as part of the description and leave the sales price blank
