## Comment on Theta

wipro

spot-559

strike-580

580CE

Premium-5.75

delta=.401,gamma-=0079,theta=-.207

if spot moves 10 points in 10 days the-

new premium= 5.75 + 10(.401) + 10(-.207)=9.76-2.07=7.69

if spot moves -10

new premium=5.75 -10(.401) -10(-.207)= 1.74 +2.07 = 3.81

my questions-

a) are my calculations of new premium correct?

b) when spot is moving down in call option theta is adding to premium . as spot =-10 and theta=-.207 so minus multiply by minus becomes plus.But it should not be the case as premium should decrease??