Sold RSU under "Long-term txns basis is reported to the IRS". The cost basis on 1e is 13,300.02. Adjusted cost basis on supplemental is 14,777.80. Which one should I use?

[MarilynG1]

Since you know your correct Cost Basis, say NO to 'Employee Stock' when entering your 1099-B.  Type in the info from your 1099-B (including the incorrect Cost Basis), and check the box that says 'the cost basis is incorrect or missing..'

Continue to the screen where you can enter your Correct Cost Basis amount. 

[narayan-1979]

Thankyou.

I don't know which one is the correct cost basis, that is my confusion.

The one in 1e is different from the one in supplemental. But I think the one in 1e is reported to IRS I think, so if I use the one in supplemental there will be difference between what is being reported to IRS vs what is being filed. So, my question is which one should I use when I don't know which one is correct?

[GeorgeM777]

You will use them both in that you will report the original basis, that is, the $13,300.02.  Enter that amount in the appropriate box in TurboTax.  Then you will see a screen which will give you the option to adjust/correct your basis.  On that screen you will enter the cost basis as reflected on the Supplement you received.  

You tax return should reflect your original cost basis, plus the difference between the original and the supplement expressed as an adjustment.  The cost basis used to report a gain or loss will be the amount on the Supplemental form you received.  By reporting your original cost basis to the IRS, your return will accurately reflect what the IRS received.   However, your return will also accurately reflect the adjustment that was made in light of the information you received in the Supplemental form.  Keep your Supplemental form so you can justify, if requested, the adjustment you made to the original cost basis. 

@narayan-1979