If you have a Thrift Savings Plan, you have one of the best retirement vehicles in the country — remarkably low costs and a clean menu of funds. The hard part isn't the account. It's deciding how much to put in each fund, and when to change it.
Ask ten people for the "best" TSP allocation and you'll get ten answers, most of them a gut feeling dressed up as a rule. We'd rather give you a framework you can actually reason about. The core idea is simple and well supported by decades of market history: hold more in the growth-oriented stock funds when retirement is far away, and gradually shift toward stability as it gets closer.
Farther from retirement, allocations commonly tilt toward the stock funds (C, S, I) for growth. Closer to retirement, they commonly raise the F and G funds to cushion against a bad year at the worst possible time. The mixes below are illustrative starting points — not a prescription for your situation.
First, the five funds in one breath
You only have five core building blocks, which is a feature, not a limitation:
- C Fund — large U.S. companies (tracks the S&P 500). The workhorse of most portfolios.
- S Fund — small and mid-sized U.S. companies. Higher growth potential, bumpier ride.
- I Fund — developed international stocks. Diversifies away from a single country's fortunes.
- F Fund — U.S. investment-grade bonds. Modest returns, and a counterweight to stocks.
- G Fund — government securities. Uniquely, it has never posted a negative year. This is your ballast.
If you'd like a deeper look at what each one holds and how it behaves, our TSP fund guides break them down one at a time. For the allocation question, what matters is the balance between the three stock funds and the two stability funds.
The framework: your allocation should follow your time horizon
The single most important variable isn't the market's mood this quarter — it's how many years until you'll need the money. Time is what lets a portfolio recover from downturns, and it's the reason a 35-year-old and a 63-year-old should not hold the same mix. Here's an illustrative glide path.
| Stage | C | S | I | F | G | Stocks |
|---|---|---|---|---|---|---|
| 30s · growth | 45% | 25% | 15% | 10% | 5% | 85% |
| 40s · build | 45% | 20% | 12% | 15% | 8% | 77% |
| 50s · consolidate | 40% | 15% | 10% | 20% | 15% | 65% |
| 60+ · preserve | 30% | 10% | 8% | 22% | 30% | 48% |
Illustrative allocations for discussion, not individual recommendations. Your own risk tolerance, other savings, and retirement date should adjust these.
In your 30s: let growth do the heavy lifting
With three decades ahead of you, your biggest risk isn't a market crash — it's being too cautious and arriving at retirement short. This is the time to hold the most in stocks. A heavy tilt to the C and S funds captures U.S. growth, with the I fund adding international breadth. A downturn now is almost a gift: you keep buying at lower prices for years before you need a dollar of it.
In your 40s: keep growing, add a little ballast
Your balance is now large enough that swings feel real. You still want stocks to dominate, but nudging the F fund up smooths the ride without meaningfully slowing your growth. This is less about defense and more about not being surprised.
In your 50s: protect what you've built
The math quietly flips in this decade. The gains from an extra few percent in stocks start to matter less than the damage a bad year could do right before you retire — the problem advisors call sequence-of-returns risk. Raising the F and G funds is how you defuse it. You're not abandoning growth; you're making sure a rough patch at 58 doesn't reset your timeline.
60 and beyond: stability first, growth second
Even in retirement you likely need some growth — your savings may need to last 30 years. But the G fund now earns its keep as ballast, and the F fund provides income-like stability. A roughly balanced mix keeps you ahead of inflation while sharply reducing how much a single bad year can hurt.
Where most people go wrong
- Setting it once and forgetting it. An allocation that was right at 35 is too aggressive at 60. Drift is the silent problem.
- Hiding in the G fund too early. It feels safe, but decades in the G fund is how you fall behind inflation and undershoot your number.
- Chasing last year's winner. Piling into whichever fund just did best is the opposite of discipline — and usually late.
- Reacting to headlines. The plan should change because your time horizon changed, not because of a scary week.
The part that actually matters: staying disciplined
A good allocation is only useful if you hold it through the uncomfortable moments and adjust it for the right reasons. That's the whole idea behind the TSP Edge strategy — a rules-based model portfolio that flags when a change is warranted, so your allocation follows evidence instead of emotion. Most months, it tells you to do nothing, which is usually the correct and hardest answer.
Whatever you decide, put a number on it before you change anything. Model your current mix, then a more disciplined one, and see the difference over 20 years. It's the fastest way to turn "that sounds about right" into a decision you can stand behind.
