Kelly Criterion Position Sizer

## Kelly Criterion Position Sizer

**Inputs**
- Stock: {TICKER}
- Win probability (p): {P}%  ← your estimated probability the trade works
- Payoff ratio (b): {B}x    ← expected gain / expected loss (e.g., 2x = $2 gained per $1 lost)
- Loss probability (q): 1 – p = {Q}%

**Kelly Formula**
f* = (b × p – q) / b
f* = ({B} × {P} – {Q}) / {B}
f* = ____%

**Fractional Kelly (recommended)**
Full Kelly is mathematically optimal but causes extreme drawdowns.
Use ½ Kelly or ¼ Kelly in practice:
- ½ Kelly position size = ____%
- ¼ Kelly position size = ____%

**Guardrails**
- Never exceed your max single-name limit regardless of Kelly output.
- Max single-name limit: {MAX}% of portfolio.
- Recommended position: min(½ Kelly, max single-name limit) = ____%

**Expected Value Check**
EV = p × gain – q × loss
EV = {P} × (b × bet size) – {Q} × bet size
EV per $100 invested: $___

**Verdict**
- Kelly says: ___% (full) → ___% (½ Kelly)
- Your max limit says: {MAX}%
- **Recommended position size: ____%**
- Positive EV trade: Yes / No. Proceed only if EV > 0.