Suppose if spot is at 200 of any stock
and I do following trades
sell 200 CE and PE option
buy 210 CE and buy 190 PE option of the same underlying stock and same expiry.
now if on expiry day if spot is at 220 then would I be required to pay more than the premium paid for 210 long call option? Given that I already have 200 short CE option?
Yes, as and when Long Stock Option position becomes ITM in last 4 days of expiry, exchange will block physical delivery margin and the margin requirement will increase, irrespective of you holding offsetting position.
This margin increases in phased manner from expiry minus 4 days. You can learn more about this here.