About 45 celebrities were reportedly part of a group of 90 social media influencers who recently received letters from the Federal Trade Commission (FTC) “educating” them about the government’s advertising disclosure requirements.

This was an issue that needed to be tackled, given that the dollar amount of endorsement contracts between brands and social media influencers—such as celebrities, athletes and reality stars—are reportedly as high as seven figures. Violating FTC advertising requirements could cost influencers and brands a lot of money—not to mention reputational injury. In the past, FTC enforcement of advertising rules was focused on brands, however social media influencers are increasingly on the FTC’s radar as a result of the rise of Instagram and other social media platforms as marketing tools. Given the high financial stakes involved and the influencers’ ability to reach millions of consumers, the FTC is keeping a close eye on influencers and their posts.