S Fund vs
Backtest S Fund vs IWMJun 2, 2003 – Oct 2, 2026, TSP-S for the S Fund, IWM for IWM, TSP-S sets the start date
Growth of $10,000
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Key metrics
| Return | S Fund | IWM |
|---|---|---|
| Final balance | $113,341 | $86,487 |
| Total return | +1,033.41% | +764.87% |
| CAGR | +10.96% | +9.69% |
| Calendar years | S Fund | IWM |
|---|---|---|
| Best year | +38.35% | +38.70% |
| Worst year | −38.32% | −34.14% |
| Positive years | 17 of 22 | 16 of 22 |
| Risk | S Fund | IWM |
|---|---|---|
| Max drawdown | −57.43% | −58.64% |
| Longest drawdown | 3.2 years | 3.6 years |
| Volatility (annualized) | 21.97% | 23.64% |
| Risk-adjusted | S Fund | IWM |
|---|---|---|
| Sharpe ratio | 0.58 | 0.51 |
| Sortino ratio | 0.81 | 0.72 |
| Calmar ratio | 0.19 | 0.17 |
Trailing returns
| Period | S Fund | IWM | S Fund − IWM |
|---|---|---|---|
| YTD | +13.45% | +15.14% | −1.70% |
| 1Y | +12.55% | +16.54% | −3.99% |
| 3Y | +19.86% | +18.69% | +1.17% |
| 5Y | +6.29% | +6.14% | +0.15% |
| 10Y | +11.37% | +9.89% | +1.48% |
| 15Y | +13.05% | +11.85% | +1.20% |
| 20Y | +9.94% | +8.54% | +1.40% |
Rolling returns
| Period | S Fund median | IWM median | More often ahead |
|---|---|---|---|
| 1Y | +14.00% | +11.22% | S Fund 68% |
| 3Y | +10.88% | +9.68% | S Fund 81% |
| 5Y | +9.03% | +7.74% | S Fund 98% |
| 10Y | +10.31% | +8.97% | S Fund 100% |
Worst drawdowns · S Fund
| Decline | Peak | Bottom | Recovered | Length |
|---|---|---|---|---|
| −57.4% | Oct 2007 | Mar 2009 | Dec 2010 | 3.2 years |
| −41.7% | Feb 2020 | Mar 2020 | Aug 2020 | 6 months |
| −36.2% | Nov 2021 | Jun 2022 | Nov 2024 | 3 years |
| −27.2% | Apr 2011 | Oct 2011 | Mar 2012 | 11 months |
| −26.8% | Dec 2024 | Apr 2025 | Aug 2025 | 9 months |
| Decline | Peak | Bottom | Recovered | Length |
|---|---|---|---|---|
| −58.6% | Jul 2007 | Mar 2009 | Feb 2011 | 3.6 years |
| −41.1% | Aug 2018 | Mar 2020 | Nov 2020 | 2.2 years |
| −31.9% | Nov 2021 | Jun 2022 | Nov 2024 | 3 years |
| −28.9% | Apr 2011 | Oct 2011 | Sep 2012 | 1.4 years |
| −27.5% | Nov 2024 | Apr 2025 | Sep 2025 | 10 months |
Annual returns
| Year | S Fund | IWM | S Fund − IWM |
|---|---|---|---|
| 2017 | +18.22% | +14.58% | +3.64% |
| 2018 | −9.26% | −11.12% | +1.86% |
| 2019 | +27.97% | +25.39% | +2.58% |
| 2020 | +31.85% | +20.03% | +11.82% |
| 2021 | +12.45% | +14.54% | −2.08% |
| 2022 | −26.26% | −20.48% | −5.77% |
| 2023 | +25.30% | +16.83% | +8.47% |
| 2024 | +16.93% | +11.38% | +5.55% |
| 2025 | +11.38% | +12.66% | −1.28% |
| 2026to Oct 2 | +13.45% | +15.14% | −1.70% |
About S Fund vs IWM
Both hold smaller US companies. The S Fund holds every US stock the S&P 500 leaves out, mid-size companies included. IWM, an iShares ETF, tracks the Russell 2000, the smallest 2,000 of the 3,000 largest US companies.
The S Fund returned 11.0% a year from Jun 2003 to Oct 2026, against 9.7% for IWM. Both fell furthest in 2007–2009, the S Fund by 57.4% and IWM by 58.6%. The S Fund beat IWM in 14 of 22 full years and in every rolling 10-year period.
Uses daily closing prices with dividends reinvested. Fund fees are included, but not taxes or trading costs. The comparison starts on Jun 2, 2003, when TSP-S's prices begin.