Which means, from the research I've done, that they buy off the shelf deigns already made in china from a multitude of suppliers. Theses suppliers may make minor changes and most also include custom dial prints for a logo and laser engraving for the bracelet and case back, a good example is Deep Blue and LumTec which I happen to own one of each.
Some suppliers offer ETA movements, etc.
Think about it, how much money would it cost to build your own custom watch from the ground up; equipment, and employees, supplies...you get the idea. It's way cheaper to source those designs and tweak them a little still using the supplier and call them your own...Made in (fill in the blank).