Did you already file your return? Then yes you would need to amend. How to amend
https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/00/27577
You have to enter any 1099-Int, 1099-Div and 1099B for sales. You might have a consolidated statement. That will have sections for 1099-Int and 1099-Div and 1099B. You need to enter each section in the right place. So read it carefully and look for headings…1099-Int for interest or 1099-Div for Dividends and 1099B for sales.
You can import the 1099 from the broker or mutual fund or enter it manually. If you are using the Online version you need to use Premier to enter 1099B for investment sales.
You should get a 1099B for sales.
Enter a 1099B under
Federal Taxes Tab (Personal for Home & Business)
Wages & Income
Then scroll down to Investment Income,
Then Stocks, Mutual Funds, Bonds, Other - click Start or Update
For stock and mutual fund sales you have to enter the purchase date and cost from your own records to figure the gain or loss. Most 1099Bs and imported information only report the sale info and even if they did report the cost you can't trust it to be right. Especially in the cases of gift stock, inherited stock, or certificates transferred from another broker, they don't have the information. And they might have made a mistake. You need to double check their amounts.
