I got a 1099-R that has box 2a "unknown" and no box 2b. What to do?

[Jerry6]

If I leave both 2a and the check marks for 2b blank, it treats the gross distribution in box 1 as untaxable.  Is this correct?  I don't think so because there's tax taken out in box 4.

[macuser_22]

Leave box 2a blank.    Box 2b is not on a CSA 1099-R.

Sounds like a CSA 1099-R and not a regular 1099-R.   Be sure that you choose the CSA type.

The taxable amount is determined by how you answer the followup questions.  If you used the simplified method last year then you should continue to.   

Enter a 1099-R here:

Federal Taxes,
Wages & Income
(I'll choose what I work on - if that screen comes up)
Retirement Plans & Social Security,
IRA, 401(k), Pension Plan Withdrawals (1099-R).

OR  Use the "Tools" menu (if online version left side) and then "Search Topics" for "1099-R" which will take you to the same place.

Be sure to choose which spouse the 1099-R is for if this is a joint tax return.

Be sure to pick the correct 1099-R type: Standard 1099-R, CSA-1099-R, CSF-1099-R, RRB-1099-R.

[NOTE: When you get to the "Your 1099-R Entries" screen where you can add another 1099-R, use "continue" to keep going as there are additional interview questions after that screen in most cases. You can always return as shown above.]ll taxable.

[edited]

[macuser_22]

Above answer edited.

[Jerry6]

It's says CSF-1099-R in one place and 1099-R in another.  It's a Statement of Survivor Annuity Paid that my Mom received each month from my Dad's pension at the OPM.  If I leave 2a blank, it automatically populates it with what's in box 1.  I don't get asked about simplified or general at the end.  This is because I answer yes to the question "For the years you received this distribution, was the total amount shown on the form the amount you paid tax on?"  This is an assumption because my Mom has passed and I'm preparing her final return.  I hope it's a reasonable one because I cannot answer the questions that the simplified page asks me.

[macuser_22]

That is probably correct.  Use the CSF type then.  

The simplified method is used to prorate after-tax contributions (basis)  that was in the account and starts the first year that the pension was paid and every year after.  It is not common to have such a basis.

You would need to look at past tax returns to find that, but if this was a survivor annuity the basis (if any) would probably be very small anyway.

As a general reference I suggest that you read IRS Pub 559 (Survivors, Executors, and Administrators) for a lot of good information about filing the final return and estate return and other requirements.

<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/p559.pdf">https://www.irs.gov/pub/irs-pdf/p559.pdf</a>