If it's 9b, then you have a problem, because it means that the OPM did not keep track of any after-tax contributions you made to your pension while you were working. If that's true, shame on them.

The others above made reference to the "simplified" method. This is needed for taxpayers who have "basis" in their pension, that is, who have made after-tax payments to their pension while they were still working.

The thing is that since you have already paid tax on after-tax contributions, you don't have to pay tax again when these dollars are distributed back to you.

However, you don't get to pick and choose which dollars come back to you each year; the IRS has a formula for determining what percentage of each yearly distribution is "return of basis" (i.e., non-taxable) and what is earnings (i.e., taxable). This is the Simplified Method referred to above.

If you never made any after-tax contributions to your pension, then 100% of your pension is taxable. Don't worry, a lot of taxpayers don't make after-tax-contributions. Just set box 2a to be the same value as box 1 and go on, telling TurboTax that this really is your taxable amount.

BUT, if you want to try something else, call the OPM and ask them what the total of your after-tax contributions is...and if they say they don't know, ask them who else were you working for with the exact same pension so that they don't about the after-tax contributions.

This is one of the most frequent questions about 1099-Rs for pensions, so I over-answered this so that you would understand your situation better.

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JamesG1

Hopefully, you have an amount in box 9b. If so, TurboTax Online will use the simplified method to determine the taxable portion for box 2a of your CSA 1099-R. Presume that:

Monthly payments were received,
Payments started in 2023, and
That box 7 is code 7.

You will need to know:

The amount of the employee contributions (should be in box 9b),
The date the annuity started,
The number of months that payments were received in 2023,
The age of the recipient when the annuity started,
The age of other beneficiaries (if there are any), and
Was the recipient under the retirement age for the plan.

Follow these steps:

Down the left side of the screen, click Federal.
Down the left side of the screen, click Wages & Income.
You may need to click Add more income.
Scroll down to Retirement Plans and Social Security, click on the dropdown menu.
Click Start/Revisit to the right of IRA 401(k) Pension Plan Withdrawal (1099-R).
At the screen Who gave you a 1099-R, select Office of Personnel Management (CSA 1099-R).
At the screen Any Periodic Payments? select Yes, got regular payments from this retirement account.
At the screen Payment Start Year select Yes started getting payments in 2023.
At the screen Let’s figure out how much is taxable, select I need to figure out how much of this money I took out is taxable.
At the screen Enter Annuity Information enter required information. Plan Cost should be in box 9b.
At the screen Enter Ages enter required information.