According to the American ToysRUs Database, the main line of Transformers 4 toys can not be sold (by major retailers who have to answer to Hasbro) before May 17th.

The (preview) "First Edition Optimus" should be out around February, and then the tidalwave of Movie toys hits stores on Saturday May 17th.


(it will also mean the stores will be winding back on their Transformers stock levels in the month or two before that date)