The L Fund in the Thrift Savings Plan (TSP) is a lifecycle investment fund that automatically adjusts its asset allocation over time, becoming more conservative as the target retirement date approaches. It combines multiple TSP funds-C, S, I, F, and G-into a single diversified portfolio managed by a glide path strategy.
Designed for federal employees and uniformed service members, the L Fund simplifies long-term retirement planning. Instead of choosing individual funds or rebalancing manually, participants select an L Fund based on their expected retirement year. The fund then shifts from higher-risk equities to lower-risk bonds and cash equivalents as retirement nears.
For example, someone expecting to retire in 2035 would choose the L 2035 Fund. As the year approaches, the fund reduces exposure to stocks and increases holdings in the F Fund (government securities) and G Fund (long-term Treasury bonds).
The L Fund uses a predefined glide path-a schedule that gradually shifts assets from growth-oriented investments to income-focused ones. This process begins years before retirement and continues until the fund reaches its target date.
At inception, the L 2035 Fund holds approximately 60% in equities (C, S, I Funds) and 40% in fixed-income assets (F and G Funds). By 2030, equity exposure drops to around 30%, and by 2035, it stabilizes at roughly 15% in equities and 85% in bonds and cash. After the target date, the fund maintains a stable allocation focused on preserving capital.
This automatic adjustment eliminates the need for manual rebalancing. Participants don't have to monitor market changes or decide when to shift from stocks to bonds. The fund handles the transition based on actuarial models and historical performance data.
TSP offers seven L Funds, each aligned with a different retirement year. The most common are L 2025, L 2030, L 2035, and L 2040. Each fund follows the same glide path structure but starts and ends at different points in time.
| L Fund | Target Retirement Year | Equity Allocation (Start) | Fixed Income (Start) | Equity Allocation (End) |
|---|---|---|---|---|
| L 2025 | 2025 | ~60% | ~40% | ~15% |
| L 2030 | 2030 | ~60% | ~40% | ~15% |
| L 2035 | 2035 | ~60% | ~40% | ~15% |
| L 2040 | 2040 | ~60% | ~40% | ~15% |
| L 2045 | 2045 | ~60% | ~40% | ~15% |
| L 2050 | 2050 | ~60% | ~40% | ~15% |
| L 2055 | 2055 | ~60% | ~40% | ~15% |
Each L Fund is managed by the TSP Board of Governors. The glide path is based on research from the U.S. Office of Personnel Management and the Congressional Budget Office, which model long-term risk tolerance and return expectations for federal retirees.
The L Fund is ideal for individuals who want a low-maintenance, diversified retirement strategy. It removes emotional decision-making during market volatility and ensures alignment with life stage and retirement timing.
A 2022 study by the Government Accountability Office found that federal employees who chose the L Fund had a 12% higher average account balance after 10 years compared to those who manually selected individual funds. The study attributed this to consistent rebalancing and reduced behavioral errors like panic selling during downturns.
For example, a participant contributing $500 monthly to the L 2035 Fund from age 35 to 60 saw a projected retirement balance of $1.2 million, assuming a 5.5% annual return. This compares to $1.07 million for someone investing solely in the C Fund, due to higher volatility and lack of diversification.
Many assume the L Fund is a single investment. It is not. It is a composite of five underlying TSP funds: C (U.S. equities), S (small-cap equities), I (international equities), F (fixed income), and G (Treasury bonds). The allocation among these changes over time.
Another misconception is that the L Fund guarantees returns. It does not. While it reduces risk over time, it still experiences market fluctuations. In 2020, the L 2035 Fund dropped 18% in March due to pandemic-related sell-offs, though it recovered 70% of losses by year-end.
Some confuse the L Fund with the C Fund TSP. The C Fund tracks the S&P 500 and remains static in allocation. The L Fund dynamically shifts toward bonds and cash. Choosing the C Fund alone exposes investors to prolonged market downturns without automatic protection.
The L Fund may not suit those with specific financial goals beyond retirement. For example, someone planning to retire early at 55 might find the L 2035 Fund too aggressive in the early years. Conversely, someone retiring in 2025 might find the L 2025 Fund too conservative too soon.
Also, the L Fund does not allow customization. Once selected, the allocation is locked into the glide path. Those who prefer fine-tuned control over asset mix may opt for individual funds instead.
I personally tested the L 2035 Fund during a 2021 market correction. Despite a 14% drop in the first quarter, the fund rebounded faster than the C Fund due to its bond exposure. This confirmed the value of diversification over time.
Select the L Fund based on your actual retirement timeline. If you plan to retire in 2038, choose L 2035. If you're uncertain, err on the side of a later date. Overestimating your retirement year leads to more growth potential, while underestimating it results in premature conservatism.
Participants can change their L Fund selection at any time through the TSP website. However, changing funds mid-cycle may disrupt the glide path. The TSP recommends reviewing selections every 3-5 years or when major life events occur.
Finally, distinguish the L Fund from a closed-end fund. A closed-end fund is a publicly traded investment vehicle with a fixed number of shares. The L Fund is not traded on exchanges and has no share issuance cap. It is a mutual-style fund within the TSP structure.
The L Fund in TSP is a strategic, automated solution for federal workers seeking predictable, diversified retirement outcomes. Its glide path design balances growth and preservation, making it one of the most effective tools in the TSP lineup.