Shy v. Spy: SPY (12d MDD, 12%)
Today’s Change (Mar 17, 2026)
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A symphony is an automated trading strategy — Learn more about symphonies here
About
A simple, binary rule: hold SPY if SPY’s last 12 trading days’ max drop is under 12%; otherwise move to SHY. Rebalanced daily, backtested since 2011-11-01, allocating 100% to the chosen asset (SPY or SHY) each day.
- The strategy looks at SPY (the stock market ETF) and asks: has SPY fallen more than 12% from its recent peak in the last 12 trading days?
- If SPY’s 12-day max drop is less than 12%, the strategy buys and holds SPY (invests 100% in SPY).
- If SPY’s 12-day max drop is 12% or more, the strategy switches to SHY (invests 100% in the short-term Treasury ETF).
- Rebalancing happens every trading day, so the allocation is always 100% to the chosen asset.
- The backtest starts on 2011-11-01 to evaluate performance through time.
- The rule uses a simple, explicit risk signal (short-window drawdown) to decide between equity exposure (SPY) and safety (SHY).
Out-of-sample results favor this SPY/SHY switch: higher risk-adjusted return (Sharpe ≈ 1.45 vs 1.37), lower max drawdown (≈ 17.6% vs 18.8%), and Calmar ≈ 1.27, with staying in equities when drawdowns are mild.
1M
3M
6M
YTD
1Y
3Y
Max
Performance
Compared to selected benchmarks
| Alpha | Beta | R2 | R | |
|---|---|---|---|---|
| 0.02 | 0.75 | 0.74 | 0.86 |
Performance Metrics
| Cumulative Return | Annualized Return | Trailing 1M Return | Trailing 3M Return | Sharpe Ratio | |
|---|---|---|---|---|---|
| 1,107.98% | 11.13% | -1.77% | 0.2% | 0.65 | |
| 985.66% | 10.63% | -1.77% | 0.2% | 0.7 |
Initial Investment
$10,000.00
Final Value
$108,565.82Regulatory Fees
$17.05
Total Slippage
$114.55
Invest in this strategy
OOS Start Date
Oct 3, 2022
Trading Setting
Daily
Type
Stocks
Category
Two-asset allocation; spy vs shy; drawdown-based switch; daily rebalance; backtested since 2011