Maximum position size is the total number of open positions you can have at any time. Total open positions are the maximum number of contracts for all products.
Example: If your maximum position size is ten lots, you can have 4-CL open positions, 3-ES open positions, and 3-NQ open positions.
Maximum Position size as it relates to Micro Products: The maximum position size is the same across all products, whether micro or mini products. In the same example above, if you are trading ten micro-ES contracts, you will not be able to trade any additional contracts for any instrument.
The exception to this rule is if you upgrade your account to a micro-only, you can trade the specified number of contracts in the upgraded plan. You cannot trade any “mini” products in the micro-only account.