Lot Size (in number of contracts) is a contract’s minimum trading unit and minimum position unit. Order quantity and position size need to be exact multiples of the contract’s Lot Size. Order quantity not in multiples of Lot Size, will be rejected.
*Please refer to the individual contract specification page for each contract’s Lot Size.*For example, a contract with a Lot Size of 100 would allow order quantities of 100, 200, 500, or 1000 contracts. It would reject quantities of 1, 5, 10, 35, 125, or 250 contracts. Similarly, a user may have a position size of 100, 200, 500, or 1000 contracts, but not 1, 5, 10, 35, 125, or 250 contracts.
From time to time it may be necessary to increase the Lot Size for a contract. In this situation, orders and positions may be rounded down to the nearest Lot Size, meaning that the “odd lot” portion of the position will be closed out.