nothing more is needed just give retail people only span margin for credit/debit spread and strategy around it and i understand exchange risk n clearing corp risk here increase the margin in last 2 days of expiry it is simple but charging 40k to 50k for a nifty spread where losses are fixed at let say approx 5k to 8k it is lunatic no where in the world margin are so high....150% of max risk is also fine but fixed this 4.4x of max risk that too floating.