Own the underlying and buy an OTM put as downside insurance.
| Parameter | Default | Description |
|---|---|---|
| strike_pct | 0.95 | Put strike (5% OTM) |
| dte | 45 | Days to expiration |
A protective put owns the underlying asset and buys an OTM put (95% of spot) to cap downside risk. It is portfolio insurance — the put limits losses below the strike while preserving full upside participation. The cost is the put premium, which reduces net returns. The strategy is equivalent to a long call in terms of payoff shape. Backtested with 45 DTE cycles, measuring combined stock + put P&L as a percentage of the entry price.
# Protective Put: own stock + buy OTM put
for entry in monthly_entries:
S = spot_at_entry
K = round(S * 0.95 / 5) * 5 # 5% OTM put
T = 45 / 365.25
premium = black_scholes_put(S, K, T, r, sigma)
S_exp = spot_at_expiry
stock_pnl = S_exp - S
put_payoff = max(0, K - S_exp)
pnl = stock_pnl + put_payoff - premium
pnl_pct = pnl / S * 100| Symbol | Return % | Sharpe | Max DD % | Win % | Avg/trade % | Trades |
|---|---|---|---|---|---|---|
| SPY | +64.0% | 0.79 | +7.9% | +79.0% | +3.4% | 19 |
| QQQ | +73.1% | 0.68 | +10.0% | +79.0% | +3.9% | 19 |
| IWM | +72.3% | 0.59 | +19.0% | +63.2% | +3.8% | 19 |
| DIA | +55.5% | 0.77 | +8.0% | +68.4% | +2.9% | 19 |
| Avg | +66.2% | 0.71 | +11.2% | +72.4% | — | 19 |