text: correct spelling of m&m's? why is m&m's not spelled m&ms, as in plural of m&m?   ' is used for possession. "m&m's" candies were first marketed by forrest mars sr. and r. bruce murrie.  they used the first initial of both of their last names, and the apostrophe "s" denotes their ownership of the idea and the trademark rather than the fact that there are more than one in a bag.