Last dealing day refers to the final day on which a trader can trade a particular futures or options contract. On the last dealing day, the contract expires and any open positions must be settled by the trader. Depending on the exchange and contract specifications, the last dealing day may occur on a specific date or day of the month, or it may be relative to the contract’s expiration date, such as occurring a certain number of days before the expiration date. It’s important for traders to keep track of the last dealing day to avoid any unintended consequences of holding open positions beyond the expiration date.