How to amend form 1099-B to report capital gains/loss because what was reported to the IRS by former employer was $0.00 in box 1e?

[david-mateo-lopez]

And what code do I use?

[JohnB5677]

If you haven't filed your tax return yet, you do not have to amend it.  However, the process to correct the basis will be the same.

To post investments:

1. Sign into TurboTax
2. There is a Sidebar to the left
3. Under Federal
4. Select Wages & Income
5. In the main body, scroll down to Investments and Savings (1099-B, 1099-INT, 1099-DIV, 1099-K, Crypto) 
6. Depending on what you've already posted, you may see different screens
7. If you've already entered transactions, select the account to change
8. [Edit]
9. Choose the stock (Use the Pencil)
10. Under the Cost or other basis 
11. Choose The cost basis is incorrect or missing on my 1099-B.
12. Make the changes