Your TSP catch-up contributions changed on January 1, 2026. If you are 50 or older and earned over $150,000 last year, the IRS just made a decision for you. Here is what actually happened.

You did everything right

You waited until the kids were done with college, you got the mortgage under control, and somewhere around 52 you finally had room in the budget to max out your TSP and then some. You turned on catch-up contributions. You picked traditional, because that's what you've always done, and you liked watching your taxable income drop every pay period.

Then this year your Leave and Earnings Statement started looking different. Your catch-up money is going somewhere it wasn't going before. Your taxable income didn't drop the way you expected. And nobody at your agency called to explain it.

Here's the thing. A federal law passed in 2022 quietly changed how catch-up contributions work for higher earners, and the change took effect January 1, 2026. If you're 50 or older and you made more than $150,000 last year, your TSP catch-up contributions are no longer yours to categorize. They're going to Roth. Not because you chose it. Because the IRS says so.

Let me walk you through exactly what happened, who it hits, and what it means for your TSP retirement planning — because depending on your situation, this is either a minor annoyance or a real shift in how you should be thinking about your last few working years.

First, the 2026 numbers you actually need

Before we get into the rule change, let's put the current limits on the table. These changed for 2026, and a surprising number of people are still contributing at last year's rate without realizing it.

• Regular elective deferral limit: $24,500
• Standard catch-up (age 50 and older): an additional $8,000, for a total of $32,500
• Enhanced catch-up (ages 60, 61, 62, and 63): an additional $11,250, for a total of $35,750

That third one deserves its own paragraph, because it's the most underused provision in the entire Thrift Savings Plan. If you turn 60, 61, 62, or 63 at any point during 2026, you get a bigger catch-up window than everybody else. It's sometimes called the "super catch-up," and it exists for exactly four years of your life. The year you turn 64, it drops back to the standard $8,000.

Four years. That's the window. If you're in it right now and you're contributing at the standard catch-up rate, you're leaving $3,250 of tax-advantaged space on the table every single year — and you'll never get those years back.

Now the change: the mandatory Roth catch-up

Here's the rule in plain English.

Starting January 1, 2026, if your prior-year FICA wages from your federal agency exceeded $150,000, every dollar of catch-up contribution you make must go into the Roth side of your TSP. You can still make regular contributions traditional. But once you hit the $24,500 pre-tax maximum and roll into catch-up territory, that money is going Roth whether you selected it or not. Your payroll office handles the switch automatically.

A few details that matter more than they look like they matter:

It's based on last year's wages, not this year's. Your 2026 treatment depends on what you earned in 2025 — specifically the Social Security wages reported in Box 3 of your W-2. Someone who got a big promotion in 2026 might not be affected until 2027.

It's per-employer. The wages counted are the ones paid by the agency that sponsors your plan. This gets interesting for anyone who changed agencies mid-year.

The threshold moves. The original number written into the law was $145,000. It's indexed for inflation in $5,000 increments, which is how we got to $150,000 for 2026 determinations. It will keep climbing, which means the pool of federal employees this affects shifts a little every year.

Why this is a bigger deal for federal employees than for most people

Let me be direct. For a lot of private-sector workers, this rule is a shrug. For federal employees in their late fifties and early sixties, it lands differently, and here's why.

You are one of the few groups of American workers who will retire with a real pension. A FERS annuity — 1% of your high-3 average salary for every year of service, or 1.1% if you retire at 62 or later with at least 20 years — is fully taxable income for the rest of your life. It doesn't stop. It gets a cost-of-living adjustment. And it stacks on top of Social Security, which is also largely taxable at your income level.

Which means a lot of federal retirees discover something uncomfortable in year one: their tax bracket didn't go down. Sometimes it went up. They spent thirty years deferring taxes into a traditional TSP on the assumption that they'd be in a lower bracket later, and then later showed up and the bracket didn't cooperate.

So when the IRS forces your catch-up dollars into Roth, it isn't necessarily working against you. For a lot of federal employees, having more money on the Roth side is exactly what their retirement tax picture needed. The problem isn't the outcome. The problem is that it happened to you instead of being a decision you made on purpose, with your actual numbers in front of you.

The federal benefits system was not designed to explain itself to you. That gap between what the rules do and what anyone tells you about them — that's the whole game.

What HR won't tell you about this

Your HR office will confirm the rule exists. They will point you to a bulletin. That is their job, and they do it correctly.

What they will not do is sit down with your high-3, your service computation date, your projected annuity, your TSP balance split between traditional and Roth, your spouse's income, and your expected Social Security claiming age, and tell you what your marginal tax rate is likely to be at 67. That is not compliance work. That's planning work. Different job entirely.

And that is where the money actually lives. The difference between a federal retiree who sequenced their traditional and Roth withdrawals with intention and one who just took money from wherever was convenient is not a rounding error. Over a 25-year retirement, with Medicare Part B premiums and IRMAA surcharges keyed to your income, it's a number with a lot of zeros in it.

Three things to actually go check this week

1. Pull up your most recent LES and find your catch-up line. Confirm where those dollars are landing. If you're over the wage threshold and you still see catch-up going traditional, something is wrong and your payroll office needs to know.

2. If you're turning 60, 61, 62, or 63 this year, check your contribution election. The enhanced catch-up doesn't turn itself on. Verify you're capturing the full $11,250, not the standard $8,000.

3. Look at your traditional-to-Roth ratio. Not the dollar amounts — the ratio. If 95% of your TSP is traditional and you're within eight years of retiring, that's a conversation worth having with somebody who understands how a FERS annuity interacts with a tax bracket.

The part that matters

You have spent decades earning one of the strongest retirement packages in America. Nobody is going to take it from you. But the difference between collecting it and maximizing it comes down to a series of decisions that mostly get made by default — including this one, which just got made for you by a law you probably never heard of.

Have you run your numbers? Not your balance. Your numbers. What your annuity will actually be, what it will be taxed at, and whether the money you're setting aside right now is going to the right side of the ledger.

If the honest answer is no, that's not a failure. The system was built to be complex and it succeeded. But it is worth fixing while you still have working years left to adjust.

Start with your Federal Retirement Blueprint. It takes a few minutes, it's free, and it will show you where your plan actually stands — including whether your traditional and Roth balance is set up for the retirement you're planning or the one that just happens to you. Get your Federal Retirement Blueprint at quiz.fedsecure.org.

Frequently Asked Questions

What is the TSP catch-up contribution limit for 2026?

The standard TSP catch-up contribution limit for 2026 is $8,000 for participants age 50 and older, on top of the $24,500 regular elective deferral limit, for a combined total of $32,500. Participants who turn 60, 61, 62, or 63 during 2026 qualify for an enhanced catch-up limit of $11,250, bringing their combined total to $35,750.

Do I have to make my TSP catch-up contributions Roth in 2026?

You must make catch-up contributions on a Roth basis if your prior-year FICA wages from your federal agency exceeded $150,000. This requirement took effect January 1, 2026 under Section 603 of the SECURE 2.0 Act. If your prior-year wages were at or below the threshold, you may still choose traditional catch-up contributions.

How does the TSP know whether the Roth catch-up rule applies to me?

The determination is based on the Social Security wages your employing agency reported in Box 3 of your prior-year W-2. Your payroll office applies the rule automatically once you reach the pre-tax contribution maximum, so no action is required on your part for the switch itself.

Is the mandatory Roth catch-up rule bad for federal employees?

Not necessarily. Because a FERS annuity and Social Security are both taxable income, many federal retirees find themselves in a similar or higher tax bracket after retirement than before it. Additional Roth savings can reduce lifetime taxes and help manage Medicare IRMAA surcharges. Whether it helps or hurts depends on your specific projected retirement income.

Can I still contribute to a traditional TSP in 2026?

Yes. The mandatory Roth requirement applies only to catch-up contributions for participants above the wage threshold. Your regular contributions up to the $24,500 elective deferral limit can still be made on a traditional pre-tax basis regardless of income.