BOX 2a on 1099R states UNKNOWN what does this mean

[texyooper45]

Taxable amount on 2a of the 1099R states UNKNOWN

[Bsch4477]

Ignore it. It just means that the issuer takes no responsibility for determining the taxability of the distribution. 

[CatinaT1 · Accepted solution]

Seeing "UNKNOWN" in Box 2a of your 1099-R is essentially a message from the payer (the bank or pension administrator) saying they don't know how much of the disbursement you might have already paid taxes on in the past. 

It is up to you to determine the taxable amount. In most cases, it is either the full amount or a calculation based on your "basis" (after-tax contributions).

Most retirement distributions are 100% taxable because the money was put in "pre-tax." However, if you ever contributed money from your own paycheck that was already taxed (after-tax contributions), you are allowed to get that specific money back tax-free. Because the payer might not have records of your contributions from 20 or 30 years ago, they mark it as "UNKNOWN" to avoid giving you the wrong tax advice.

When entering this into TurboTax:

1. Leave Box 2a empty on the entry screen.
2. Check the first box in Box 2b (Taxable amount not determined).
3. TurboTax will then ask follow-up questions to help you calculate the taxable portion.

The most common scenarios for box 2a being unknown:

Standard 1099-R (Private Sector / 401k / IRA)

If this is from a standard company pension or a traditional IRA, and you know you never made after-tax contributions: You can simply enter the same amount from Box 1 into Box 2a and the entire distribution is treated as taxable income. This is the most common outcome for private-sector employees.

Public Sector 1099-R (Federal / CSA / CSF / Military)

This is where "Unknown" is most frequently seen. The Office of Personnel Management (OPM) often lacks your final contribution data. TurboTax will walk you through using the Simplified Method. You will need to know your "Plan Cost" (the total after-tax money you put in, usually found in Box 9b) and your age when you retired. The software will spread your tax-free "basis" over your expected lifetime, making a small portion of your pension tax-free every year.

[OldSchoolShaver12]

I am in a similar situation and TurboTax did not prompt me on how to determine the taxable amount. For reference, I retired from federal service (FERS) on 1 Aug 2024 and received partial payments until November 2025 at which time I received a large back payment. I am divorced and my ex wife is entitled to a portion. The 1099R reflects UNKNOWN in block 2a and there is also a note that gross annuity was reduced by $$$ (purposely leaving out number) for ex spouse. I do know from reading that a small portion of the FERS pension is not taxable based on previous employee contributions and that number is easy to determine and was also provided by OPM in separate correspondence. The difference between leaving block 2a blank in TurboTax and actually entering a figure results in either several thousand dollar refund or payment due of a few hundred dollars. Just looking for answers as there seems to be conflicting information even within the TurboTax discussions. Thanks

[AmyC]

Spouse: If the ex-spouse receives a payment directly from OPM via a court order (apportionment), they are responsible for the taxes on their portion. OPM should issue them their own 1099-R.

While working, money paid into the system with after dollars is returned to you during retirement to reduce the taxable portion. The simplified method is used to determine the recovery amount each year. You need to keep track of amounts claimed through the years.

Your taxable amount is generally:

Box 1 (Gross)-  Tax-Free Recovery Portion = Taxable Amount

Payment due - a large amount due may stem from including the money your ex-wife got in taxable income. This should not be part of your tax return.  It could stem from your large back payment and not having enough tax withheld. It could be the simplified worksheet was not used.

Entry:

1. Delete and Re-add: If you’ve already messed with the 1099-R, delete it entirely and start fresh to clear any "stuck" background logic.
2. Select the Correct Form: When re-adding, specifically select "CSA-1099-R" (the form for OPM) rather than a standard 1099-R.
3. The Box 2a Trick: Enter Box 1 exactly as shown. In Box 2a, leave it blank. Do not enter "0" or "Unknown."
4. Continue through the screens. Look for a question asking if this was a "Periodic Payment." Answer Yes.
5. Annuity information Total amount taxable? Answer no
6. Plan Cost: Enter your total employee contributions (the number you said was easy to determine/provided by OPM).
7. Start Date: 1 Aug 2024.
8. Age: Your age on the date you retired.

The program will calculate the simplified method for you to determine the taxable income.

You may want to verify that the numbers on your 1099-R are correct and belong to you alone.

@OldSchoolShaver12