European Call Option (Black–Scholes)
C = S0N(d1) − K e−rT N(d2)
European Put Option (Black–Scholes)
P = K e−rT N(−d2) − S0 N(−d1)
d1 and d2
d1 =
[ln(S0/K) + (r + ½σ²)T] / (σ√T)
d2 = d1 − σ√T
Where
- S0 = current underlying price
- K = strike price
- r = risk-free rate (continuous)
- T = time to maturity (years)
- σ = volatility
- N(·) = standard normal CDF
Equity options use Black–Scholes; futures options apply Black–76 conventions.
Core Greeks (under Black–Scholes)
- Delta (Δ) — Call: Δ = N(d1), Put: Δ = N(d1) − 1
- Gamma (Γ) — Γ = N'(d1) / (S0 σ √T)
- Vega — Vega = S0 N'(d1) √T
- Theta (per year) — Call and put formulas use combinations of N(d1), N(d2), r, and σ
- Rho (ρ) — Sensitivity of option value to a 1-unit change in interest rate r