Set your allocation, pick any stretch — 2008, 2020, 2022 — and watch it compound month by month through the market's worst years. Built for one question: how much would you have kept when the market fell?
Pick a stretch of history and set your C, S, I, F, and G allocation. It compounds your allocation month by month through the real market — then lays it against the TSP Edge model, so you can see the drawdowns you'd have lived through, not just the growth.
You've seen it hold up. Now project the same funds forward 20 years — your allocation carries straight over.
The TSP Lifecycle funds are built for simplicity — they hold their allocation straight through every market, calm or falling. That feels safe until the market drops. Across 20 years of real history, the deepest damage came from the losses they were never built to sidestep — and a big loss at the wrong time is far harder to undo than a weak year of returns.
In 2008, the L 2030 fund fell 27.5%. The TSP Edge model's rules-based rotation moved defensively before the worst of the decline — ending the year with a far smaller loss. Every dollar lost in a crash requires more than a dollar to recover.
A −27% loss requires a +37% gain just to break even. Every year your TSP spends recovering is a year it isn't compounding forward. The TSP Edge model avoids this trap by rotating defensively — not after the crash, but before it deepens.
The L Funds rebalance mechanically, regardless of market conditions. A rules-based monthly update responds to what's actually happening — rotating among C, S, I, F, and G funds when conditions warrant, holding when they don't.
TSP Edge publishes disciplined, rules-based research, distilled into one clear action for your TSP account. No daily monitoring. No complex decisions. Approximately five minutes per month.
On the first trading day of each month, Retirement Edge publishes the TSP Edge model portfolio — the model's current allocation across the C/S/I/F/G funds this month.
Review the update on your dashboard. Log into tsp.gov and check your current allocation. Most months, no change is needed — you simply hold.
When a change is called for, submit an interfund transfer (IFT) at tsp.gov. You're in control of every decision. The whole process takes about five minutes.
Daily updates would exhaust your IFT allowance and create costly whipsawing. Annual rebalancing misses real market shifts entirely. Monthly updates sit in the sweet spot: responsive enough to avoid major downturns, infrequent enough to avoid noise.
The model typically changes allocations three to four times per year — meaning most months, you simply hold with no action needed. When a change is called for, one IFT is all it takes.
See the Full TSP Edge Research →TSP Edge has backtested data through every major market correction since 2006 — the full period of available TSP fund history. Here's how it performed when the L Funds were at their worst.
The L 2030 fund lost 27.5% in 2008. TSP investors who held the L Fund through the crash needed years to recover. The TSP Edge model's rules-based rotation moved toward the G and F Funds before the steepest declines, significantly limiting the drawdown.
TSP Edge: Far smaller loss than L 2030A decade of strong equity growth. TSP's C and S Funds performed well — and the TSP Edge model captured most of that growth while rotating defensively during short-term corrections. Starting from a higher 2009 base (less damage absorbed) compounded significantly over 10 years.
TSP Edge: Strong compounding from higher baseIn March 2020, U.S. equities fell 34% in 33 days. TSP investors who held C and S Funds through the drop saw large temporary losses. The TSP Edge model's monthly update positioned defensively before the worst of the drop, then rotated back into equities for the recovery.
TSP Edge: Positive year overallBoth equities (C/S/I) and bonds (F Fund) fell simultaneously in 2022 — an unusual double loss that hit even conservative TSP allocations. The TSP Edge model rotated into the G Fund, which is guaranteed by the U.S. government and never loses value, protecting the balance.
TSP Edge: G Fund rotation protected balanceAcross the full backtested period — Jan 2006 through Dec 2025 — including the 2008 crisis, 2020 crash, and 2022 bear market, TSP Edge produced a 14.35% backtested CAGR vs 7.33% for the TSP L 2030 Fund. $10,000 grew to $146,136 vs $41,118.
TSP Edge: 14.35% CAGR vs 7.33% L 2030 · $146,136 vs $41,118
The backtest shows what your allocation survived. The TSP growth calculator projects what it could become from here — same funds, forward view.
It replays your exact C, S, I, F, and G allocation month by month through real market history — January 2006 through December 2025, including the 2008 crash, the 2020 COVID drop, and the 2022 bear market. It lays the TSP Edge model beside your allocation so you can see the drawdowns you'd have lived through, not just the ending balance. All figures are backtested and hypothetical.
The Thrift Savings Plan offers five individual funds: C Fund (S&P 500 large-cap stocks, 11.01% historical CAGR), S Fund (small-cap U.S. stocks, 9.53%), I Fund (international developed markets, 5.91%), F Fund (bond index, 3.12%), and G Fund (government securities, guaranteed principal, 2.85%). The L Funds are target-date blends that shift toward bonds as your target date approaches. All CAGRs are backtested Jan 2006–Dec 2025 per Portfolio Visualizer.
Log into your TSP account at tsp.gov and submit an interfund transfer (IFT). The TSP allows two free interfund transfers per calendar month — plus unlimited moves into the G Fund at any time. Changes submitted before market close on a business day typically take effect that same evening. The full process takes about five minutes.
Because a deep loss at the wrong time does lasting damage. A −27% year needs a +37% gain just to get back to even, and every year spent recovering is a year not compounding forward. An average return hides that — the worst year is where real portfolios get hurt. The TSP Safety Check reports the worst 12-month stretch for both your allocation and the TSP Edge model, so you can compare what you'd have kept, not just what you'd have earned on paper.
It follows a disciplined, rules-based monthly update. When markets weaken it rotates toward the defensive G and F Funds — the G Fund is government-guaranteed and never loses principal — then rotates back toward the C, S, and I Funds as conditions recover, typically changing allocation only three to four times a year. Across the 2008, 2020, and 2022 downturns, that rotation is why its worst backtested year (−10.8%) was far shallower than the L 2030 Fund's (−27.5%).
It uses 240 monthly return observations — January 2006 through December 2025, the full period of available TSP fund history — sourced from Portfolio Visualizer. Working at monthly resolution means any window you pick is honest, even one that begins or ends mid-crash (like the depths of 2020). The F Fund is modeled with a total-bond-market proxy and the L Fund with the TSP 2030 lifecycle proxy. All results are hypothetical and backtested.
Yes. Uniformed service members enrolled in the Blended Retirement System (BRS) or the legacy High-3 retirement system with active TSP accounts use the same C/S/I/F/G/L funds as civilian federal employees. This calculator and the TSP Edge model portfolio works identically for both FERS civilian employees and military service members.
No. Retirement Edge is a financial research and newsletter publication — not a registered investment adviser. This calculator and the monthly TSP Edge update are published for informational and educational purposes only. You make every investment decision independently. We operate under the publisher exemption, Section 202(a)(11)(D) of the Investment Advisers Act of 1940.
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