We can’t all be that one guy who went 100% C Fund and never flinched through any crisis. Use this visualizer to see which mixes had drawdowns you could stomach today—and still sleep well at night. If you’re the “all-in C” hero, good for you. (A slow, unenthusiastic clap echoes from someone in the back row.) For the rest of us mere mortals, let’s analyze the market numbers from history and learn.
P.S. If you’re a TSP L Fund user, this calculator isn’t for you. You’re already letting the target date team do the heavy lifting. No judgment.
How This Thingy Works (Assumptions)
Uses daily TSP fund prices and shows total return.
Rebalancing annually is already baked into the portfolio backtest results.
Earliest start auto-picks the first date where all selected funds have valid prices from TSP.gov (TSP.gov only goes back to May 31, 2003).
While it uses data from TSP.gov, TSP Portfolio Analyzer is hypothetical and for educational purposes only. Enjoy!
How to Use This Portfolio Analyzer
Set the % weights for C, S, I, F, and G (must total 100%).
Optionally enable Compare vs. Alternate Allocation and enter a second mix.
Choose a start and end date (or leave blank to auto-span available data) and click Run Backtest.
Lastly, dont forget to turn on the Flux Capacitor. 😜
TSP Portfolio Backtest
Model any custom allocation · Compare two portfolios · See how your mix would have performed
C Fund
%
S Fund
%
I Fund
%
F Fund
%
G Fund
%
✓ 100% — ready
⚔️
Compare Two Portfolios
Add a second allocation and see them go head-to-head on every metric
OFF
C Fund
%
S Fund
%
I Fund
%
F Fund
%
G Fund
%
✓ 100% — ready
Portfolio B uses the same date range, starting balance, and contribution amount.
Annual rebalancing is applied at the first trading day of each calendar year.
Portfolio Growth
Performance Summary
All figures based on historical price data with annual rebalancing.
My Portfolio
Comparison Portfolio
Annual Returns by Year
⚠ Important disclaimer: Past performance does not guarantee future results.
This tool is for educational and illustrative purposes only — not financial advice.
Backtests have inherent look-ahead bias and do not account for taxes, fees outside of fund ERs,
or behavioral factors. TSP fund data sourced from tsp.gov.
Always verify important decisions with your agency HR, OPM, or a licensed financial advisor.
🔗 Shareable link:
Disclaimer
The TSP Portfolio Analyzer is for education and entertainment only.
It “replays the tape” to show how different mixes of the C, S, I, F, and G funds would have performed.
No, we can’t fire up the DeLorean to change the timeline.
If you want personalized advice, talk to a licensed pro — this widget is not your fiduciary.
Past performance isn’t a promise, even at 88 miles per hour…Where we’re going, we still need diversification.
