Many of our clients have Minimum Advertised Price (MAP) clauses in their vendor contracts, and we pay attention to developments in the space.  When Amazon breaks MAP, it’s often large enough that the rest of the players feel the pain.  They call the manufacturer, who then threatens to cut Amazon off.  Most of the time, it’s an empty threat- but when the product is stronger than the retailer’s brand or they simply have the guts to play the long game, they follow through.

http://www.huffingtonpost.com/2014/06/16/amazon-hachette-knife-wusthof_n_5492582.html