When filing 1040X to correct cost basis on 1099B, do I enter the correct case basis, or do I enter the difference between the original and the correct cost basis?

[lschwabenbauer]

E*Trade cost basis did not include an amount already taxed in my W2, so I need to amend. Figured out how to create the 1040X in TT, but unsure which number to report - the accurate cost basis, or the difference between the accurate number and the number in my original return. Also - cost basis is the only number I am including on 1040X, correct? Thank you!

[TomYoung · Accepted solution]

I'm pretty sure you enter the trade as you should have entered it in the first place.  If that's all you're correcting then that's all you need change. 

In any case you need to print out and mail the Form 1040 X so simply look to see that the correct adjustment - the amount of compensation income you didn't include in your basis on your original "as filed" income tax return - shows up in Column B of the Form 1040X.

Tom Young