There is a rule that the Olympic Committee has in place that Michael Phelps may have broken. As a result he may have to return a few of the medals that he won in London recently!This past Olympics brought NBC millions in revenue from advertisers and will go down as a record setting 2 weeks not only for the athletes but for the NBC bank account. That being said, Michael Phelps may have to return a few medals he won after some officials sasy he broke a rule known as "Rule 40."

CNBC reports:

"A new IOC regulation, called Rule 40, prohibits athletes from appearing in ads for non-Olympic sponsors from July 18 to Aug. 15. According to the IOC’s 19 page explainer, Rule 40 is designed to prevent ambush marketing, defined as non-Olympic sponsors trying to associate themselves with the Olympic brand"

Phelps appeared in a recent ad for Louis Vuitton that some say violated the rule because the photos and the ad were published during the games.