Rule 40 is a by-law in the official Olympic Charter, and it states that “No competitor, coach, trainer or official who participates in the Olympic Games may allow his person, name, picture or sports performances to be used for advertising purposes during the Olympic Games” without the express consent of the IOC board.
Under the original rule, only official Olympic sponsors—big consumer brands, like Coca-Cola, McDonald’s, Panasonic and Visa, that have paid about $200 million each—get consent.