1 9 6 4 ), ▁John ▁L int ner ▁( 1 9 6 5 a , b ) ▁and ▁Jan ▁M oss in ▁( 1 9 6 6 ) ▁independently , ▁building ▁on ▁the ▁earlier ▁work ▁of ▁Harry ▁Mark ow itz ▁on ▁divers ification ▁and ▁modern ▁port folio ▁theory . ▁ ▁Sh ar pe , ▁Mark ow itz ▁and ▁M erton ▁Miller ▁joint ly ▁received ▁the ▁ 1 9 9 0 ▁Nobel ▁Memorial ▁Prize ▁in ▁Econom ics ▁for ▁this ▁contribution ▁to ▁the ▁field ▁of ▁financial ▁econom ics . ▁ ▁Fischer ▁Black ▁( 1 9 7 2 ) ▁developed ▁another ▁version ▁of ▁C AP M , ▁called ▁Black ▁C AP M ▁or ▁zero - beta ▁C AP M , ▁that ▁does ▁not ▁assume ▁the ▁existence ▁of ▁a ▁risk less ▁asset . ▁ ▁This ▁version ▁was ▁more ▁robust ▁against ▁empir ical ▁testing ▁and ▁was ▁influ ential ▁in ▁the ▁w ides p read ▁ad option ▁of ▁the ▁C AP M . ▁ ▁Formula ▁ ▁The ▁C AP M ▁is ▁a ▁model ▁for ▁pr icing ▁an ▁individual ▁security ▁or ▁port folio . ▁For ▁individual ▁se cur ities , ▁we ▁make ▁use ▁of ▁the ▁security ▁market ▁line ▁( S ML ) ▁and ▁its ▁relation ▁to ▁expected ▁return ▁and ▁system atic ▁risk ▁( beta ) ▁to ▁show ▁how ▁the ▁market ▁must ▁price ▁individual ▁se cur ities ▁in ▁relation ▁to ▁their ▁security ▁risk ▁class . ▁The ▁S ML ▁enables ▁us ▁to ▁calculate ▁the ▁reward - to - ris k ▁ratio ▁for ▁any ▁security ▁in ▁relation ▁to ▁that ▁of ▁the ▁overall