Forbes ranked the most valuable sports team brands by calculating the amount by which their enterprise value exceeds that of a typical team in the same sport.
American football franchise Dallas Cowboys were rated the most valuable team brand in the world with a value of $896m (£677m).
United were named the fourth-most valuable team brand across all sports with a value of $564m.
Barcelona (fifth) and Real Madrid (seventh) were the only other football teams in the top 10.
"The world's most valuable sports brands have been racing ahead of their peers," Forbes said.
Its study found that the worth of the 40 of the most valuable sports brands had increased 200% during the course of the past decade.
Among athletes, Roger Federer held on to his position as the world's most valuable athlete with a brand worth of $37.2m, with LeBron James coming in second and Usain Bolt in third.
Real Madrid forward Cristiano Ronaldo had the fourth-most valuable brand among athletes at $21m, while his Barcelona rival Lionel Messi was ninth with a brand value of $13m.