the Black-Scholes model
noun [ S ]
FINANCE, STOCK MARKET uk/ˌblækˈʃəʊlz ˌmɒd.əl/ us/ˌblækˈʃoʊlz ˌmɑː.dəl/ (also the Black-Scholes option pricing model)a mathematical method of calculating whether an option (= the right to buy shares within a particular period of time) has a fair value, based on the price of similar shares, interest rates, etc.:
Then options are awarded on the basis of the Black-Scholes model, which roughly means the option is worth a third of the underlying share.