Banknifty Calls with the highest OI expired today in the money
I always thought that on expiry day, the calls and puts with the highest OI will end up at Rs. 0 by having the operators keep the closing price below the highest OI call strike and above the highest OI put strike. However today (11th Oct 2023) I noticed that even though the 45500 strike had the highest OI for calls, Banknifty closed the day at Rs. 44516.9 and the 44500 calls closed the with with premium Rs. 15.9. Can someone help me understand how this came out, how common is this? I have been thinking up strategies to short sell options based on OI data but now I’m shocked by this happening.