I just found the E*trade supplemental info with the adjusted cost basis for my 2023 vested RSUs. Should I amend my 2023 return to fix the cost basis ($0) that I reported?

[ftang101]

The 1099-b that I received from E*trade for my RSUs showed 0 for the cost basis. That’s what I reported in TurboTax and as I result I owed and paid much more taxes than expected. I read online that sometimes brokers don’t report the correct cost basis so I looked at the tax documents in my E*trade account and found a Supplemental Information document that shows the adjusted cost basis for the RSUs that vested last year. Should I have reported this adjusted cost basis and is this a valid reason to amend my 2023 tax return?

[maglib]

@ftang101  Your cost basis should be adjusted to reflect the amount that you had received in taxable income via w-2's for RSU's.  Yes, file an amended return as you most likely will get a refund.  You are not required to amend but, if it means a refund, then it may be worth it.

To amend your return, select your product and follow the instructions.  First MAKE SURE TO SAVE YOUR RETURN AS AMENDED so that you DO NOT LOSE THE ORIGINAL FILE.

1. Write down the original refund or balance due amount(s) for your Federal and State, if applicable, income taxes. We recommend you check the paper/PDF copy of your return(s), or your banking records to verify the correct amount.
2. Sign in to the TurboTax account where you prepared your  return. In Tax Home, scroll down to Your tax returns & documents, and choose proper year. If you have not already done so, we recommend that you print a copy of your original  tax return for your records by selecting Download/print return (PDF).
3. Select Amend (change) return and then select Amend Using TurboTax Online.
4. On the OK, let’s get a kickstart on your 202x amended return screen, choose TurboTax sent me an email, then Continue.
5. On the What did we contact you about? screen, choose Something else then Continue.
6. On the Tell us which 202x return(s) you want to amend screen, select the proper year Federal return, then Continue. Your federal refund/balance due tracker will usually reset to $0, this is normal.

Note: If you have a state return, also select 202x state return and go through the state amendment steps.

7. On the Here’s the info for your amended federal return screen, select Done.
8. On the Tell us why you’re amending your return screen, enter TO CORRECT erroneous cost basis on RSU's, then Continue.
9. On the Let’s confirm your mailing address screen, confirm your mailing address, then Continue.
10. On the Do you want to designate $3 to a presidential campaign fund? screen, select your answer and then Continue.
11. On the Do any of these less common situations apply to you? Screen, select None of these apply to me, then Continue.
12. On the Let’s confirm your Social Security number and birth date screen, check the information and then Continue.
13. On the Accuracy’s everything. Time for a quick review. screen, select Check my info.
14. On the Your federal return’s in great shape screen, select Continue.
15. If you do not have a state return, skip to step 16.

To amend your state return, go through these steps:

1. On the Let’s get your state taxes done right screen, select Continue.
2. On the Let’s amend your state taxes screen, select Amend next to the state.
3. Continue through the state screens and answer any state specific questions until you reach the Let’s Make Sure You’re Ready to Review screen, select Yes, I’ve entered everything and let’s review. Then Continue.
4. On the Ready to Review Your State Return screen, select Continue.
5. On the Smart Check Results screen, select Continue.

16. On the Smartcheck results screen, select Continue.
17. On the Let’s get your return ready to file screen, select Check my return.
18. On the Just about ready to file. But first… screen, select Continue.
19. On the Let’s take care of these details now screen, select Review and fix any errors.

[ftang101]

Thank you for the detailed response. It is extremely helpful. I will wait until I receive my California state tax refund before amending my return. Couple of questions:

- Your instructions were for TurboTax online. I used TurboTax Premium installed on my home computer. Are the instructions the same?

- Also, if I need to fix something else (for the same tax year), can I do it at the same time or will that require submitting a second amended return?

[fanfare]

Make the corrections you know about.

Form 1040-X becomes your new tax return,

If Part III Explanation space is too small attach another sheet.

@ftang101