Most title reigns: since 2020
Most separate reigns as undisputed UFC champion.
Reigns are derived from championship bouts. When a belt was vacated or stripped outside a title fight, the reign is shown ending at the next title fight in that division, so a few run long; a title awarded without a fight (José Aldo's in 2010, for one) starts at the champion's first UFC title fight.
An interim champion promoted to undisputed starts a new reign on the promotion date.
41 fighters.