TSP L Funds for feds with a pension: which one, and the glide-path problem

1. How the L Funds are built

Each Lifecycle Fund is a fixed mix of the five individual TSP funds: G, F, C, S, and I. There is nothing in an L Fund that you could not build yourself from those five. What the L Fund adds is a target allocation designed by the Federal Retirement Thrift Investment Board’s investment consultants to sit as close as possible to the efficient frontier for a given time horizon, automatic quarterly adjustment of that target as the horizon shortens, and rebalancing back to target at the end of every trading day. It costs a net administrative expense of 0.033% to 0.034% plus investment expenses of 0.002% to 0.008%, essentially the same as holding the individual funds.

The year in the fund’s name is its target date: the year you expect to begin withdrawing the money. The TSP says this plainly in its own fund information, and it matters more than most participants realize. The date is not “the year I retire.” It is “the year I start spending this money.” For many federal employees those are different years, and section 5 is about why.

When an L Fund reaches its target year it merges into the L Income Fund, and any money in it takes on L Income’s allocation. L 2025 did this in 2025. L 2030 will do it in 2030. There is no notice and no option to opt out other than moving the money first.

2. Every L Fund’s allocation

As of December 31, 2025, from the TSP’s May 2026 fund information. The stock share is C plus S plus I.

Two patterns are worth noticing. The stock mix barely changes across the funds: roughly half C, an eighth S, and a third I at every horizon, which is the Board’s view of an efficient global stock portfolio and the reference split used in the C Fund concentration guide. What changes is the stock share, from 99% for someone thirty years out to 28% for someone withdrawing today. The L Income Fund has been moving gradually toward more stock since 2019, under a ten-year plan the Board adopted after concluding the previous 20% stock share was too low; it will settle at a constant allocation once that transition is complete.

3. The glide path and the assumption behind it

Plot the stock share against years to target and you get the glide path: steep in the last fifteen years before the target, flat at nearly all-stock before that.

The glide path encodes an assumption: that the participant’s TSP is their main retirement asset, that withdrawals from it will fund essential spending from the target date onward, and that a large loss just before or just after that date is the risk to protect against above all others. Every one of those is correct for the typical private-sector target-date investor, who has Social Security and a 401(k) and nothing else. The design is not a mistake. It is a design for a participant most federal employees are not.

4. Why a FERS pension changes the math

In a retirement portfolio, bonds have one job: deliver reliable income that does not fall when stocks do, so the retiree never has to sell stocks at a bad time to eat. A FERS annuity does that job better than any bond fund. It is guaranteed by the U.S. Treasury, it arrives monthly for life, it is adjusted for inflation from age 62, and it never has to be sold. Social Security does the same. For most federal retirees, these two income streams already are the bond allocation. The question is how to count them.

The simplest method is to capitalize the pension: ask how large a bond portfolio would be needed to produce the same income. At a 4% yield, roughly the G Fund’s 2025 rate, a $36,000 pension is the income of a $900,000 bond portfolio. A $36,000 pension plus $30,000 of Social Security is the income of $1.65 million. Now add the TSP.

Read the first row slowly. A retiree with a full FERS pension who puts the entire TSP in the L Income Fund has, across everything that will fund her retirement, about 10% in stocks. That is an allocation most advisers would consider too conservative for an 85-year-old. She is 60. Over a 25-year retirement, the difference between a 10% and a 36% overall stock share is the difference between a TSP that keeps pace with inflation and one that does not.

The capitalization method is a rule of thumb, not a valuation. A pension has no principal to leave to heirs and cannot be spent faster in a bad year, so it is not identical to $900,000 of bonds. But for the one question that matters here, “how much of my retirement income is already guaranteed?”, it gives the right answer, and the answer for most FERS retirees is “most of it.” The hidden wealth of a federal pension works through the valuation in more depth.

5. Pick by when you need the money, not when you retire

The TSP’s selection table says to choose the L Fund whose target range covers “when you expect to need the money” or when “your TSP withdrawals will begin.” Most participants read that as their retirement year. For a fed, the two dates often diverge by a decade or more, in a predictable pattern:

• Retirement to 62: the pension and the FERS supplement arrive. Many retirees draw little or nothing from the TSP in these years, or draw only for discretionary spending.
• 62 onward: Social Security replaces the supplement, often at a higher amount. If the retiree is bridging to 70, TSP draws are heavier in this window and then fall.
• 73 or 75: required minimum distributions begin on the traditional balance whether or not the money is needed. Roth TSP is exempt.

So the honest “when do I need this money?” answer for a retiree whose pension and Social Security cover essential spending is often not for a decade or more, and then only in part. A 57-year-old retiring in 2031 in that position is not an L 2030 participant. By the TSP’s own criterion she is an L 2040 or L 2045 participant, because that is when she expects to begin drawing on the money in earnest.

Contrast a retiree with a small pension from a shorter career, say $14,000 a year after an MRA+10 retirement, who needs $25,000 a year from the TSP from the first month. Her TSP is the essential-spending engine. The L Fund matching her retirement year is exactly right for her, and the standard glide path is doing precisely what it was built to do.

The test, then, is one question: will your TSP withdrawals pay for essentials or for extras? If extras, choose the L Fund by the date the extras begin, which is later than you think. If essentials, choose by your retirement date and trust the glide path.

6. Three ways to use L Funds with a pension

Approach A: one L Fund, dated later than your retirement

The simplest. Decide the year you expect to begin drawing meaningfully on the TSP, choose the L Fund whose range covers it, and hold nothing else. A retiree who expects to leave the TSP largely alone until RMDs at 73 in 2044 holds L 2045. The fund glides toward L Income as that date approaches, which is the right shape for money that will start to be spent then. The weakness: it holds only 16% G at the outset, so if she does need $20,000 unexpectedly in a bad year, she is selling stock. This approach suits retirees with a cash reserve outside the TSP or a pension with real slack in it.

Approach B: two L Funds, near and far

Hold the next three to five years of planned withdrawals in the L Income Fund and the rest in a far-dated L Fund. The L Income slice, at 72% G and F, protects the near-term draws; the far slice does the growing. A retiree drawing $20,000 a year holds $80,000 to $100,000 in L Income and the balance in L 2045 or L 2050, and once a year sells enough of the far fund to top the near fund back up. The TSP notes that holding two L Funds duplicates exposure, since both contain all five funds; that is true and harmless here, because the point is not the mix within each but the split between them. Two-fund holders should also know that the L Income slice will hold some stock, about 28%, so the “safe” bucket is not entirely safe. If that bothers you, use Approach C.

Approach C: G Fund bucket plus a far L Fund

Replace the L Income slice with the G Fund itself. Hold three to five years of withdrawals in G, everything else in a far-dated L Fund, and top up G annually from the L Fund. This is the cleanest version of the bucket strategy available inside the TSP: the near bucket cannot lose a dollar, the far bucket is a professionally managed global stock portfolio that glides on its own, and the participant makes one transaction a year. It is the approach this guide recommends for most FERS retirees who want to stay in the L Funds.

L Funds or build your own?

Every approach above can also be executed with the individual funds: a G bucket plus a C/S/I sleeve at the L Fund proportions, rebalanced once a year. The results are nearly identical and the cost is the same, so the choice comes down to two differences. First, a hand-built sleeve does not glide; it stays at whatever stock share you set until you change it, which is either a feature or a chore depending on how much attention you want to pay. Second, the L Fund carries a small F Fund allocation (5% to 7%) that a G-plus-stocks portfolio omits; over long periods the F Fund has returned more than the G Fund with more volatility, and reasonable people differ on whether it belongs in a federal retiree’s account at all. If you enjoy managing the allocation, build it and revisit the C/S/I split annually. If you would rather make one decision and one transaction a year, the far-dated L Fund is that decision, and it is a good one.

7. Four worked cases

Case 1: the classic FERS retiree

GS-13, 30 years, retiring at 57 in 2031 with a $38,000 pension, a $1,400 monthly supplement to 62, and $520,000 in the TSP. Essential spending is $60,000; pension and supplement cover $54,800, leaving $5,200 a year from the TSP until 62, then Social Security more than covers the gap. Her TSP is for extras, travel, and eventually long-term care reserve. She does not expect to draw meaningfully until 70 or later. Default choice: L 2030, since she retires in 2031. Better choice: Approach C with $30,000 in G (five years of the $5,200 gap plus margin) and $490,000 in L 2045. Overall stock share counting her pension: about 26%. Reasonable for a 57-year-old with a guaranteed floor.

Case 2: the MRA+10 retiree

GS-9, 14 years, separating at 57 in 2027 under MRA+10 with a $12,000 reduced pension, no supplement, and $260,000 in the TSP. She needs $28,000 a year from the TSP from day one. Her TSP is the essential-spending engine and the standard glide path is right: L 2030, rolling into L Income in 2030, gives her the protection the design intends. If anything she should consider whether she can postpone the annuity to reduce the draw; but the L Fund choice itself is correct as labelled.

Case 3: the two-fed household

Both retire in 2032 with combined pensions of $64,000 and expected combined Social Security of $52,000 from 67. Combined TSP $900,000. Essential spending $95,000, covered by guaranteed income from 67 with $21,000 to spare; between 2032 and 67 the supplements cover most of the gap. Their TSP has no essential job at any point. Approach A is defensible for them: L 2055 for the whole balance, an overall stock share of about 24% counting pensions and Social Security, with a $60,000 emergency fund held outside the TSP. Or Approach C with $60,000 in G and the rest in L 2055. Either way, L 2030 would leave them with a portfolio suited to someone with a tenth of their guaranteed income.

Case 4: the late starter with a large balance

Single, 63, retiring in 2028 at MRA+30 equivalent with a $41,000 pension, Social Security of $2,300 at 67, and a $1.1 million TSP built over 36 years. He wants to bridge to 70, drawing $2,800 a month for seven years, roughly $235,000. After 70, Social Security and pension exceed his spending. Approach C: $235,000 in G for the bridge, $865,000 in L 2045 (the RMD-heavy years begin in 2038). At 70 the G bucket is spent, the L 2045 balance has had seven more years of growth, and the RMDs from 75 onward are his heirs’ problem and his charitable giving, not his grocery money.

8. When the standard glide path is right

To be fair to the design, here is when a fed should take the L Fund at face value and match it to the retirement year:

• Your TSP will fund essentials from the start. Short career, MRA+10 reduction, or a pension that does not cover baseline spending. The glide path is built for you.
• You have a deferred or postponed annuity and will live on the TSP until it begins. Your TSP is your only income for those years.
• You have no cash reserve outside the TSP and know you will need lump sums. The L Income slice is your emergency fund; keep it.
• You would sell in a crash. If a 30% drop in your TSP would make you move everything to G at the bottom, a conservative allocation you can hold beats an optimal one you cannot. Know yourself.
• You are a survivor or beneficiary relying on a reduced survivor annuity, and the TSP now carries more of the load than it did.

9. Mechanics: rebalancing, roll-in, and the target-date cliff

Daily rebalancing. Each L Fund is rebalanced to its target at the end of every trading day. You never need to rebalance within an L Fund. Under Approaches B and C you rebalance between your two holdings once a year, using one of the two fund transfers or reallocations the TSP allows per month.

Quarterly glide. Every dated L Fund shifts a little more conservative each quarter. Over ten years an L 2045 participant drifts from 77% stock toward L 2035’s 66%. If you chose the fund because you wanted 77% stock, note that you will not have it for long; if you chose it because 2045 is when you need the money, the drift is the feature.

The target-date cliff. In its target year, a dated L Fund merges into L Income. For an L 2030 holder that is a move from 57% stock to 28% in a single step in 2030. Nobody will warn you. If you have concluded from this guide that L Income is more conservative than you want, set a reminder for the year before your fund’s target date to move the money to the next fund out.

Contribution allocation vs. account allocation. If you are still working, where your new contributions go and how your existing balance is invested are two separate settings. Changing the first does not change the second. A participant who moves contributions to L 2045 in 2026 still has twenty years of prior contributions sitting wherever they were.

Roth and traditional. The L Fund allocation applies across your whole account; you cannot hold Roth TSP in one fund and traditional in another. If that matters to you, it is one of the few reasons to hold Roth money in a Roth IRA instead, once both five-year clocks are satisfied.

10. Your checklist

• Write down your projected pension, supplement, and Social Security at each age, and your essential spending. The gap, if any, is the TSP’s essential job.
• Answer the one question: essentials or extras? If extras, when do they begin?
• Capitalize your guaranteed income at 4% and compute your overall stock share under the L Fund you hold today. If it is under 25% and you are under 70, you are probably too conservative.
• Choose an approach: A, B, or C. For most FERS retirees, C.
• Size the near bucket at three to five years of planned TSP withdrawals, not three to five years of spending.
• Pick the far L Fund by the year meaningful withdrawals begin. Round later, not earlier.
• Set an annual date to top up the near bucket, and a reminder for the year before your far fund’s target date.
• If still working, change both the contribution allocation and the account allocation.

11. Frequently asked questions