Heinz Ketchup is the utterly dominant brand of ketchup in America by an order of magnitude. They sell more ketchup than every other brand combined in the U.S. and it is not a monopoly. Every attempt to make some new upstart ketchup has failed, and generations are totally sold on just Heinz with a degree of brand loyalty FB would kill to get... and yet they are not a monopoly nor has it been seriously alleged that they are.