Black-Scholes-Merton (BSM) Model

Last Updated on October 19, 2025 by Admin

Notes

  • Used to determine the fair market value of a European Call or Put option

The original model was published by;

  • Fischer S. Black, Sloan School of Management, Massachusetts Institute of Technology (MIT)
  • Myron S. Scholes, Booth School of Business, University of Chicago
  • Paper: “The Pricing of Options and Corporate Liabilities”
  • Journal: Journal of Political Economy
  • Publisher: University of Chicago Press
  • Publication Date: May 1973
  • Significance: This is the original paper introducing the Black-Scholes model, providing a formula for pricing European options based on no-arbitrage principles and continuous-time finance.

The model was extended and published by;

  • Robert C. Merton, Sloan School of Management, Massachusetts Institute of Technology (MIT)
  • Paper: “Theory of Rational Option Pricing”
  • Journal: The Bell Journal of Economics and Management Science
  • Publisher: The RAND Corporation
  • Publication Date: Spring 1973
  • Significance: This paper extended and generalised the Black-Scholes framework, provided a more rigorous mathematical derivation, and showed how it could be applied to a wide range of contingent claims giving rise to the Black-Scholes-Merton model.

Assumptions

  • Risk-free interest rate
  • Constant volatility

Formula

$$Call\;Option\;\left( C \right)=SN(d_{1}) – Ke^{-rt}N(d_{2})$$

  • C = Call Option Price
  • N = Cumulative Distribution Function (CDF)
  • S = Spot Price
  • K = Strike Price
  • r = Risk-Free Interest Rate
  • T = Time to Maturity (Expiration)
  • v = Volatility

$$Put\;Option\;(P) = Ke^{-rT}N\left(-d_{2} \right)- SN\left( -d_{1} \right)$$


Black-Scholes-Merton (BSM) Calculator

* Entered as a percentage (%), i.e. 10
* Entered as a percentage (%), i.e. 20
* Entered as years (i.e. half a year = 0.5, 1 year = 1, 2 years = 2 etc.)
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d2
N(d1)
N(d2)
Price of Option (Call)
Price of Option (Put)