The UFC sent a letter on Monday to its athletes advising them that it updated its athlete code of conduct policy that will now prohibit them and their close associates from wagering on UFC events.

In the letter, Hunter Campbell, the UFC’s chief business officer, writes “In order to assist our athletes in understanding their obligations under the laws of the majority of states in which sports betting is permitted, and in further support of these integrity measures, UFC has incorporated a wagering prohibition into the UFC Athlete Conduct Policy expressly prohibiting athletes from wagering on any UFC match.”

Campbell told Yahoo Sports that athletes are still able to seek out sponsorships or deals as brand ambassadors from sports betting companies.