As published in our recent notice, In The Money (ITM) options contracts that are left to expire will devolve into futures contracts. You will need to have the required margins to hold a futures contract in such a case. The margin requirements are mentioned in our margin calculator. This is applicable to the Silver options contracts which are expiring tomorrow, 26th June.
If you have ITM options positions on expiry day but do not have sufficient margins to hold futures position before devolution, your position will be squared off anytime after 10:00 PM today.