I have observed this many times that if underlying price increases , option prelimium increases more for option which has expiry early than those which has expiry 1 month later.
For ex ,-
Call Option (ULTRACEMCO 7500 CE)premium with expiry of 29th July increased more today as compared to expriy of 27 August. In terms of percentage.
All delta and gamma should be same as strike price is same for both. And with IV is almost same too. So only theta is different and we know that theta should decrease the 29th July premium more because it will be expired in 2-3 days.
But instead I am observing opposite.
Can anyone explain this behaviour??