Star National Football League quarterback Tom Brady took a hit to his reputation Wednesday when a league-commissioned report concluded that he may have known team equipment employees were violating the rules by tampering with footballs. But despite the findings—or a potential suspension—Brady's cash flow and sponsor support are unlikely to wane.

New endorsers may not rush to plaster Brady's face on their products, but it seems unlikely that existing sponsors including Under Armour, Movado watches and Ugg will drop him, said Darren Marshall, executive vice president of consulting and research at sports marketing agency rEvolution.