I Why fund allocation matters more than tax choice
Federal employees frequently spend hours agonizing over the Traditional vs Roth TSP decision — a choice that typically affects lifetime wealth by 5-15% at the extremes. The same employees then default their entire TSP balance into the G Fund and pay no further attention. This is backwards. Fund allocation is the single largest determinant of retirement outcomes inside your TSP. A federal employee who contributes 10% of salary to Traditional TSP for 30 years and holds 90% G Fund will end their career with roughly one-third the wealth of the same employee holding an age-appropriate diversified allocation.
The reason is compound growth. Over any 20-year period in U.S. market history, diversified equity allocations have substantially outperformed bond and government securities allocations. Over 30-40 year federal careers, the differential compounds to hundreds of thousands or millions of dollars in ending wealth. Federal employees who "play it safe" by parking TSP in G Fund face a different but real risk: guaranteed underperformance of inflation-adjusted equity returns over long time horizons.
This does not mean everyone should hold 100% stocks. Age-appropriate allocation matters, and federal employees within 5-10 years of retirement need meaningful bond and G Fund allocations to protect against sequence-of-returns risk. But the default "G Fund forever" approach that many federal employees fall into is a wealth-destroying strategy dressed up as caution.
If you take away nothing else: federal employees under age 50 should hold at least 70% in the C, S, and I stock funds (or an equivalent L Fund). The G Fund is for retirees drawing down and for short-term reserves — not for wealth accumulation.
II The G Fund — Government Securities
The G Fund invests exclusively in short-term, non-marketable U.S. Treasury securities specially issued to the TSP. These securities are guaranteed by the full faith and credit of the U.S. government. The G Fund is the only TSP fund with a guarantee of principal preservation — it cannot lose nominal value. The interest rate is set monthly by the U.S. Treasury based on the average yield of outstanding marketable Treasury notes with 4 or more years to maturity. The G Fund earned approximately 4.44% in 2025 and is running at approximately 2.57% year-to-date through July 2026.
The G Fund's unique structure — a special-issue Treasury security available only to TSP — makes it slightly more attractive than money market or short-term Treasury alternatives available outside TSP. It earns the yield of longer-duration Treasuries while maintaining daily liquidity and principal protection. This is a structural advantage federal employees should use appropriately, but not overuse.
III The F Fund — Fixed Income Index
The F Fund tracks the Bloomberg U.S. Aggregate Bond Index, holding a diversified portfolio of investment-grade U.S. bonds including U.S. Treasuries, government agency bonds, mortgage-backed securities, and corporate bonds. Unlike the G Fund, the F Fund can lose value — bond prices fall when interest rates rise. The F Fund declined 1.29% in July 2026 and is running slightly negative year-to-date, illustrating that "bonds are safe" is a misleading generalization.
The F Fund is often overlooked in favor of the G Fund for the "bond" portion of a TSP allocation. This is generally a mistake — the F Fund's exposure to corporate bonds and longer-duration Treasuries typically produces higher long-run returns than the G Fund's short-Treasury exposure, at the cost of some short-term volatility. For federal employees with 10+ years to retirement wanting a bond allocation, F Fund exposure produces better long-run outcomes than G Fund exposure.
IV The C Fund — Common Stock (S&P 500)
The C Fund tracks the Standard & Poor's 500 Index, holding all 500 large-cap U.S. stocks that make up the index in the same proportions. The largest holdings track the largest U.S. companies — technology giants, major financial institutions, healthcare leaders, consumer brands. The C Fund is the flagship equity holding for most federal employees. It slipped 0.07% in July 2026 but retains a year-to-date gain of approximately 10.13%.
The C Fund's long-run historical return has been approximately 10% annually including dividends — the highest of any TSP fund over multi-decade horizons. Short-term volatility is real: the fund has experienced 30-50% peak-to-trough declines multiple times in its history. Federal employees who cannot emotionally tolerate this volatility should not hold 100% C Fund, but should also not use volatility avoidance as an excuse to hold zero equity. Some equity exposure is essential for retirement wealth building.
V The S Fund — Small Cap Completion Index
The S Fund tracks the Dow Jones U.S. Completion Total Stock Market Index, which represents all U.S. publicly traded stocks NOT in the S&P 500 — approximately 2,500-3,000 mid-cap and small-cap companies. Held in combination with the C Fund, the two together represent the full U.S. equity market at roughly market-weight (approximately 80% C, 20% S based on market capitalization).
Historical returns for the S Fund have been slightly higher than the C Fund over very long horizons, reflecting the "small-cap premium" that small companies have historically produced. The trade-off is greater short-term volatility. A common combined allocation is 60-70% C + 15-20% S, roughly approximating the full U.S. equity market at market-cap weightings.
VI The I Fund — International Stock Index
The I Fund tracks the MSCI ACWI IMI ex USA ex China ex Hong Kong Index, holding stocks from developed markets (Europe, Japan, Australia, Canada) and emerging markets (excluding China and Hong Kong). The fund was transitioned from tracking MSCI EAFE (developed markets only) to the broader ACWI IMI ex-USA index in 2024, adding meaningful emerging markets exposure. The exclusion of China/Hong Kong reflects a policy decision by the FRTIB in 2020 following concerns about investment in Chinese entities subject to U.S. sanctions.
Historical I Fund returns have been more variable than U.S. equity — international stocks outperformed U.S. stocks during the 2000s, then underperformed during the 2010s and much of the early 2020s. International exposure is a diversifier, not a return enhancer over all time periods. Federal employees typically allocate 10-25% of equity to I Fund for diversification benefit without over-weighting to international.
VII The Lifecycle L Funds
The Lifecycle Funds are professionally managed target-date funds constructed from the five individual TSP funds. Each L Fund holds a specific blend of G, F, C, S, and I designed for participants who expect to begin TSP withdrawals during a particular five-year period around the target date. As the target date approaches, the L Fund automatically shifts from more aggressive (higher C/S/I) to more conservative (higher G/F) allocation — a glide path managed by the FRTIB and rebalanced daily.
The 11 currently active L Funds:
- L Income — For participants already withdrawing or beginning withdrawals imminently. Approximately 26-30% equity, 70-74% G/F Fund fixed income.
- L 2030 — For withdrawals between 2028-2032. Approximately 40-50% equity.
- L 2035 — For withdrawals between 2033-2037. Approximately 55-60% equity.
- L 2040 — For withdrawals between 2038-2042. Approximately 65-70% equity.
- L 2045 — For withdrawals between 2043-2047. Approximately 75% equity.
- L 2050 — For withdrawals between 2048-2052. Approximately 80-85% equity.
- L 2055, L 2060, L 2065, L 2070, L 2075 — For long-horizon participants. Approximately 99% equity (mostly C/S/I).
L 2025 was retired in June 2025 as the target period ended, with its assets folding into L Income. Future retirements will follow the same pattern as target dates elapse.
The L Funds are not a separate expense — the fund holds the underlying individual funds, and expense ratios are simply the weighted average of the underlying fund expenses. This makes L Funds one of the most cost-efficient target-date fund options available anywhere.
Pick the L Fund whose target year is closest to when you expect to begin drawing TSP — not your retirement date if those differ. A federal employee retiring at 57 under MRA+30 but not planning to draw TSP until 62 (bridged by FERS pension and FERS supplement) should pick an L Fund matched to the 62 draw date, not the 57 retirement date. This preserves the equity glide path through the bridge years.
VIII Expense ratios — TSP's structural advantage
TSP expense ratios are among the lowest available in the entire retirement industry. The total expense ratios for the individual funds range from approximately 0.048% to 0.079% annually as of the most recent published data. This is a permanent structural advantage federal employees hold over private-sector 401(k) participants — one that compounds enormously over a career.
For context, the average 401(k) plan expense ratio for participants at small employers is around 0.5%, and can exceed 1% at some plans. A federal employee whose TSP balance grows to $1 million pays roughly $500-800 per year in TSP expenses. That same balance in an average small-employer 401(k) would cost $5,000 per year or more. Over a 30-year career, this differential compounds to over $200,000 in additional retirement wealth just from the expense difference — before considering any investment return differential.
Less than 1% of the roughly 170,000 investment funds cataloged on FactSet as of January 2026 reported expenses below the TSP's average 2025 total expense ratio. This is not a marketing claim — it is a genuine statistical fact. TSP is one of the cheapest retirement investment vehicles on Earth.
The practical implication: TSP is not a fund to leave for outside IRA rollovers casually. Federal employees who separate and consider rolling their TSP to an outside IRA should carefully compare the destination IRA's expense ratios against TSP's ~0.06% average before moving. Many rollover destinations charge 0.5-1.5% in combined expenses, converting a lifetime of TSP cost savings into ongoing wealth drag.
IX TSP Fund Allocation Recommender
Enter your age, risk tolerance, and career stage below. The tool returns a recommended allocation across the five individual TSP funds along with the equivalent L Fund that most closely matches.
What's the right mix for me?
Enter your age, retirement timeline, and risk tolerance. The tool applies age-based glide path principles to recommend an individual-fund allocation and the closest matching L Fund.
X Recommendations by age and career stage
The following age-based allocation ranges assume a federal employee with expected FERS + Social Security replacement of 40-60% of final salary and moderate risk tolerance. Federal employees with higher pension replacement can afford more aggressive TSP allocation because the pension itself provides bond-like income independently of TSP.
Age 20-40 (25+ years to retirement)
Recommended: 90-100% equity (C/S/I). Typical allocation 60% C, 20% S, 15-20% I, 0-5% G/F. Equivalent L Fund: L 2055 through L 2075 depending on age. At this career stage, the long time horizon absorbs short-term volatility completely and equity's higher expected returns compound powerfully. The G Fund is inappropriate at this stage — it produces guaranteed underperformance versus equity over 25+ year horizons.
Age 40-50 (15-25 years to retirement)
Recommended: 75-90% equity. Typical allocation 55% C, 15-20% S, 10-15% I, 10-20% G/F. Equivalent L Fund: L 2040 through L 2050 depending on age. The glide path begins to incorporate more bond exposure. Federal employees in this range should be maximally focused on contribution rate rather than tactical allocation — moving from a 5% contribution rate to 15% at age 42 has vastly more wealth impact than switching between L 2045 and L 2050.
Age 50-60 (5-15 years to retirement)
Recommended: 60-75% equity. Typical allocation 45-55% C, 10-15% S, 10-15% I, 15-30% G/F. Equivalent L Fund: L 2035 through L 2045 depending on age. Sequence-of-returns risk becomes meaningful — a large market decline in the 5 years before or after retirement can permanently impair wealth. Increasing bond and G Fund allocation provides protection against this specific risk. Federal employees at this stage should also be maxing out catch-up contributions ($8,000 standard or $11,250 super for ages 60-63).
Age 60-65 (approaching retirement)
Recommended: 50-65% equity. Typical allocation 35-45% C, 8-12% S, 8-12% I, 30-45% G/F. Equivalent L Fund: L 2030 through L 2035. The transition to withdrawal phase begins. Federal employees planning to draw from TSP within 5 years should ensure enough G/F to cover 3-5 years of expected withdrawals — this creates a cash-like buffer that avoids selling equities into a downturn during early withdrawal years.
Age 65+ (in retirement)
Recommended: 40-55% equity. Typical allocation 30-40% C, 5-10% S, 5-10% I, 40-55% G/F. Equivalent L Fund: L Income to L 2030. Continued equity exposure supports long-run purchasing power in what may be a 20-30 year retirement, while substantial G/F allocation provides withdrawal stability. Federal employees who plan to leave TSP to heirs (rather than fully deplete) can maintain higher equity allocation because the effective time horizon extends beyond their own lifespan.
XI L Fund vs DIY allocation
For most federal employees, an L Fund matched to their expected TSP withdrawal start date is the correct choice. L Funds provide professional-grade diversified allocation, automatic rebalancing, and cost-free glide-path management. The default assumption should be: use an L Fund unless you have a specific reason to build a custom allocation.
Reasons to consider DIY allocation across individual funds:
- You want to tilt more aggressive than the L Fund glide path. Federal employees with substantial FERS pension replacement (60%+) can support more equity risk than the standard glide path assumes.
- You want to tilt more conservative. Federal employees who cannot emotionally tolerate the equity volatility of the L Fund matched to their retirement date may need a more conservative allocation.
- You want more or less international exposure. The L Fund international allocation is roughly 30% of equity. Federal employees with strong views about international investment (either direction) may want to over- or under-weight.
- You hold employer stock or concentrated positions outside TSP. If you already have significant U.S. equity exposure through other accounts, DIY allocation lets you diversify by holding more I Fund or F Fund inside TSP.
- You want to separate the equity glide path from the retirement date. Federal employees planning to leave TSP to heirs or expecting a very long retirement can hold more aggressive allocation than the L Fund matched to their expected withdrawal start.
Reasons NOT to build a custom allocation: confidence that you can beat FRTIB-managed L Funds through tactical fund selection, market timing, or performance chasing. The overwhelming evidence from behavioral finance research shows that tactical fund switching by individual retail investors produces worse outcomes than passive glide-path allocation, primarily due to buy-high-sell-low patterns driven by emotional reactions to market movements.
XII Rebalancing and interfund transfers
TSP offers two mechanisms for adjusting your allocation:
- Interfund transfer (IFT): Moves existing balances between funds. Limited to two IFTs per calendar month that move money into any fund other than the G Fund. Unlimited IFTs are allowed into the G Fund. This limit was implemented to reduce short-term trading that raised costs for all TSP participants.
- Contribution allocation change: Directs future contributions to different funds. Unlimited — you can change contribution allocation as often as needed. This is the mechanism to use for gradual allocation shifts over time.
For federal employees using an L Fund, rebalancing is automatic — the FRTIB rebalances L Funds daily to maintain target allocations. No participant action is required.
For federal employees using DIY individual fund allocations, rebalancing frequency should be moderate:
- Once per year, on a consistent date (birthday, anniversary of TSP enrollment, tax day), is sufficient for most participants
- Or when any fund's allocation drifts more than 5 percentage points from target (a "band rebalancing" approach)
- Rebalancing more frequently than quarterly produces marginal benefit and increases behavioral risk (reacting to short-term market movements)
The most cost-efficient rebalancing method is directing new contributions to the underweight funds, rather than performing IFTs on existing balances. This avoids the 2-per-month IFT limit and requires no separate action beyond adjusting your contribution allocation.
XIII Common allocation mistakes
Mistake 1: Defaulting to 100% G Fund for "safety." The most common and costly allocation error. G Fund produces principal protection but guaranteed underperformance versus equity over long horizons. Federal employees under 50 who hold 100% G Fund are essentially guaranteeing sub-optimal retirement wealth in the name of avoiding volatility that will never affect them because they won't be drawing from the account for decades.
Mistake 2: Chasing recent performance. Moving into whichever fund had the best recent 12-month return. This produces systematic buy-high behavior. The C Fund's strong 2024-2025 returns tempt investors to move from I Fund into C Fund; when I Fund outperforms in subsequent years, they move back. This pattern of chasing yesterday's winners is one of the most reliable predictors of retail investor underperformance.
Mistake 3: Moving to G Fund after a market decline. The variant of performance chasing that does the most damage. Selling stocks after they've fallen locks in losses and misses the recovery. The March 2020 COVID crash saw a substantial fraction of TSP participants panic-move into G Fund; those who did missed most of the strongest 12-month recovery in modern market history.
Mistake 4: Ignoring international allocation entirely. Some federal employees hold 100% C Fund based on preference for U.S. equity. This overweights domestic equity relative to global market capitalization. Historical periods where international substantially outperformed U.S. equity are real and consequential — a fully home-biased portfolio has meaningful concentration risk.
Mistake 5: Selecting an L Fund based on retirement age rather than TSP withdrawal age. Federal employees retiring at 57 who won't draw TSP until 62 (bridged by FERS pension) should pick the L Fund matched to 62, not 57. Choosing L 2030 for a 57-year-old retiring in 2035 who won't draw TSP until 2040 creates unnecessarily conservative allocation during the 5-year bridge period.
Mistake 6: Frequent IFT usage. Making an IFT every month or more often. This burns the limited IFT allowance and typically reflects reactive decision-making rather than strategic allocation management. Set an allocation, use the automatic-rebalancing L Funds, and leave it alone.
30-Year Ending Wealth by TSP Allocation
Projected ending TSP balance for $10,000 annual contribution over 30 years at typical long-run returns for each allocation. Illustrates the enormous cost of over-conservative allocation.
What every federal employee should do this year
- Log into TSP.gov and check your current allocation. If 100% G Fund and you're under 55, this is your top financial priority to fix.
- If unsure what to hold, use the L Fund matched to your expected TSP withdrawal start date (not retirement date, if different). This handles allocation, glide path, and rebalancing automatically.
- If building a custom allocation, aim for age-appropriate equity exposure per Section X. Under 50: 75-100% equity. 50-60: 60-75%. 60+: 40-65%.
- Direct new contributions to the funds you want to be underweight the least. This handles most rebalancing needs without using IFT capacity.
- Rebalance no more than annually if using DIY allocation. L Fund users need no rebalancing.
- Do not react to short-term market movements. The largest wealth-destroying decisions federal employees make with TSP are panic moves to G Fund after declines and performance-chasing moves into recent winners.
- If separating from federal service, compare TSP's 0.048-0.079% expense ratio against the destination IRA before rolling over. TSP is one of the cheapest retirement vehicles available — leaving it is often financially worse than keeping it.
- Focus on contribution rate. Going from 5% to 15% of salary contribution rate matters vastly more than fine-tuning the mix between C and S. See Topic 12 on TSP Contribution Strategy.
Frequently asked questions
The TSP offers five individual investment funds: The G Fund (Government Securities Investment Fund) invests in special-issue U.S. Treasury securities and guarantees principal — it cannot lose value. The F Fund (Fixed Income Index Investment Fund) tracks the Bloomberg U.S. Aggregate Bond Index, holding investment-grade bonds. The C Fund (Common Stock Index Investment Fund) tracks the S&P 500, holding large-cap U.S. stocks. The S Fund (Small Cap Stock Index Investment Fund) tracks the Dow Jones U.S. Completion Total Stock Market Index, holding mid-cap and small-cap U.S. stocks not in the S&P 500. The I Fund (International Stock Index Investment Fund) tracks the MSCI ACWI IMI ex USA ex China ex Hong Kong Index, holding international stocks from developed and emerging markets.
The Lifecycle Funds (L Funds) are target-date retirement funds constructed from combinations of the five individual TSP funds. There are currently 11 active L Funds: L Income (for participants already withdrawing or beginning withdrawals soon) plus target-dated funds L 2030, L 2035, L 2040, L 2045, L 2050, L 2055, L 2060, L 2065, L 2070, and L 2075. Each L Fund is designed for participants who expect to begin withdrawals during a particular five-year period around the target date. The allocations automatically shift from more aggressive (higher C/S/I) to more conservative (higher G/F) as the target date approaches — a glide path managed by the FRTIB. L 2025 was retired in June 2025 and its assets moved to L Income.
TSP expense ratios are among the lowest in the entire retirement industry. As of the most recent published expense data, the total expense ratios (net administrative + investment) for the individual funds range from approximately 0.048% to 0.079% annually. The L Funds have no separate expense — they inherit the weighted expense ratios of their underlying individual funds. For context, less than 1% of the roughly 170,000 investment funds cataloged on FactSet as of January 2026 reported expenses below the TSP's average 2025 total expense ratio. Compared to the average 401(k) plan expense ratio of 0.5% or higher, TSP saves federal employees roughly 0.4-0.5% of assets annually — worth hundreds of thousands over a career.
For most federal employees, an L Fund matched to their expected retirement age is the right choice. L Funds provide diversified, professionally managed target-date allocation at no additional cost. They automatically rebalance quarterly and gradually shift toward more conservative allocation as retirement approaches. DIY allocation is appropriate for federal employees who want to tilt more aggressive or more conservative than the standard L Fund glide path, want more control over the international allocation, or have specific reasons (concentration in employer stock through other accounts, expected inheritance, unusual retirement income needs) that make the standard glide path inappropriate. The wrong reason to avoid L Funds is confidence that you can beat the FRTIB-managed allocation through tactical fund switching — the evidence overwhelmingly shows this fails.
The G Fund is safe in the sense of principal protection — the fund cannot lose nominal value. It invests in special-issue U.S. Treasury securities that guarantee the return of principal plus interest. However, the G Fund is NOT safe from inflation risk. The G Fund earned approximately 4.44% in 2025 against inflation of approximately 2.8-3%, producing only a small real return. During periods of higher inflation, the G Fund can produce negative real returns even while nominal returns remain positive. Federal employees with 15+ years to retirement who hold significant G Fund allocations are essentially guaranteed to underperform inflation-adjusted stock returns over that period. The G Fund is appropriate for stability of principal, short-term emergency reserves within TSP, and retirees drawing down assets — not as a long-term wealth-building allocation for federal employees still accumulating savings.
For federal employees using an L Fund, rebalancing is automatic — the FRTIB rebalances the L Funds daily to maintain target allocations. For federal employees using a custom allocation across individual funds, rebalancing once per year or when allocations drift more than 5 percentage points from target is generally sufficient. Rebalancing more frequently produces marginal benefit and may cause behavioral errors (selling into rebounds, buying into peaks). TSP offers two mechanisms: interfund transfers (moves existing balances between funds) and contribution allocation changes (directs future contributions to different funds). Interfund transfers are limited to two per calendar month for moves into any fund other than the G Fund; there is no limit on moves into the G Fund.
General age-based allocation guidance: Age 20-40 (25+ years to retirement) — 90-100% stocks (C/S/I), with L 2055-L 2075 as good defaults. Age 40-50 (15-25 years to retirement) — 75-90% stocks, with L 2040-L 2050 as good defaults. Age 50-60 (5-15 years to retirement) — 60-75% stocks, with L 2035-L 2045 as good defaults. Age 60-65 (approaching retirement) — 50-65% stocks, with L 2030-L 2035 as good defaults. Age 65+ (in retirement) — 40-55% stocks with growing bond/G Fund allocation, with L Income to L 2030 as defaults. These are starting points. Federal employees with substantial pension income (FERS + Social Security replacing 60%+ of pre-retirement income) can afford more aggressive allocation than the general glide path suggests because the pension provides bond-like income independently of TSP.
There is no explicit cash or money market fund inside TSP. The G Fund is the closest equivalent — it provides principal protection and daily liquidity with returns typically at or near short-term Treasury yields. Federal employees wanting cash-equivalent exposure within TSP use the G Fund for that purpose. Withdrawing from TSP to hold cash outside the plan generally produces worse outcomes due to loss of tax-advantaged status and the loss of TSP's ultra-low expense ratios. For federal employees needing genuine cash reserves for short-term expenses, a high-yield savings account outside TSP is generally the right vehicle.