The IRS gives federal employees a one-time grace period on the first Required Minimum Distribution. It lets you delay that first RMD until April 1 of the year following the year you reach RMD age. Almost everyone I talk to thinks that delay is a gift. It is, in most cases, a tax-time bomb.

The rule is in IRS Publication 575 and codified in IRC § 401(a)(9). It is not optional in the way most people assume. You can use the grace period, but if you do, you will take twoRMDs in the same calendar year — one by April 1 for the prior year, and another by December 31 for the current year. Two RMDs in one year is rarely what you want.

The schedule in concrete form.

Assume your RMD age is 73 (the current rule for federal employees born 1951–1959). Here is how the first RMD year plays out:

  • The year you turn 73— this is your “RMD year.” You must take an RMD for this year. You can take it any time during the calendar year, or you can defer it to the following April 1.
  • By December 31 of the year you turn 73— if you take the RMD during the calendar year, you have satisfied the requirement. Your second RMD (for the following year) will be due by December 31 of next year, twelve months later.
  • By April 1 of the year after you turn 73— the latest possible date for your first RMD. If you delay, you will still owe a second RMD (for the current year) by December 31, just ten months later.

So the “delay” does not give you a year of tax-deferred growth. It gives you three to four months, at the cost of two RMDs stacking in the same calendar year.

Why two-RMD stacking usually backfires.

Stacking matters because of how marginal tax rates work. Your first dollar of TSP withdrawal is taxed at your lowest ordinary bracket. Your last dollar is taxed at the marginal rate that applies to income above the threshold. Two RMDs in one year compresses two years of income into one, and the marginal rate on the second dollar tends to land higher than either RMD would have landed alone.

The same stacking also drives the IRMAA calculation two years later. Your Medicare Part B and Part D premiums in 2028 are based on your MAGI in 2026. Two stacked RMDs in 2026 raise your 2026 MAGI, which raises your 2028 IRMAA tier, which raises your Medicare premiums for as long as your income stays elevated. The April 1 grace period is therefore rarely the cheapest option.

The exceptions worth knowing.

There are cases where delaying the first RMD to April 1 actually makes sense:

  • You separated from service late in the prior calendar year and did not have time to set up your TSP withdrawal elections before year-end. The grace period lets you catch up.
  • You are coordinating the first RMD with a one-time event — a Roth conversion, a property sale, a planned low-income year — that the April 1 date actually helps.
  • Your first-RMD amount is small enough that the stacking effect does not move you into a meaningfully higher bracket. For very small TSP balances, this can be true.

For most federal employees with a meaningful Traditional TSP balance, none of those conditions hold. The default answer is: take the first RMD in the calendar year you reach RMD age. Do not delay.

The TSP’s own mechanics.

A practical note: the TSP will not let you accidentally miss an RMD. If you are receiving installment payments and your account falls below the calculated annual RMD, the TSP will issue an automatic distribution to satisfy the requirement. The number is reported on Form 1099-R, and the agency that receives it (the IRS, in most cases) is the same one that knows what you were supposed to take.

If you prefer to take your RMD as a single annual withdrawal rather than installments, the TSP allows that too — but you have to elect it, and you have to make sure the election takes effect in time to satisfy the deadline. “Out of sight, out of mind” is the most expensive mindset for RMDs.