Rules-based S&P 500 timing: flee to T‑bills when SPY is extremely hot or very volatile; buy when it’s extremely weak. In normal times, stay in SPY, but hedge to 50% T‑bills if cash trends better than bonds; otherwise remain fully in SPY.

It times the S&P 500 (SPY) using short‑term heat/weakness and a safety switch. - If SPY is extremely hot (5‑day strength > 91), move to T‑bills (BIL). - If SPY is extremely weak (< 27), buy SPY. - If very volatile (> 2.5), move to BIL. - Otherwise own SPY, then: if bonds (BND) trend better than T‑bills over ~3 months, stay 100% SPY; else go 50% SPY/50% BIL.

In out-of-sample tests, this strategy delivers stronger risk-adjusted performance than SPY: Sharpe 1.56 vs 1.31, Calmar 1.43, max drawdown 12.6% vs 18.8%, beta ~0.64. It shifts to cash on risk, preserving capital while still capturing gains.