If a lease car is 'in stock', it means it has either already been built, or is about to built imminently, and is available to be delivered in the quickest possible time - meaning you can get behind the wheel of your dream car without a frustrating wait. In stock cars have often already been delivered to a dealership, broker or leasing company and are the opposite of a 'factory order', where there's typically a much longer wait between the initial enquiry and the car rolling off a manufacturer's production line months later.