How does Option prices determine on expiry day ?

I am new to option trading.Normal days options price are nearly arround Black Scholes Model's prices but on expiry day there is big difference between these two. so how option price work on expiry day is there any model or it's just speculative way the price move with respect to underlying .


Active Member
true value of option is whats underlying + gain
if nifty is 9075 on expiry then 9000 CE will expire at R.s 75
and 9100 CE be 0

Only person that control market can win in option rest all die.
option are scam stay away from it .

Don;t believe me then paper trade option for 3 months and you will know .
it took me 10 yrs to understand that lol hope u are cleaver then me lol
Thanks for reply and suggestion.
But I am curious about How 9000 CE price move between time period of 9.15 to 3.29 on expiry day ?
what are the gain of option between this period ?

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