New York law firm Cravath, Swaine & Moore is moving away from its seniority-based compensation system, upending a hallmark of the firm’s culture that has made it a rarity in the cutthroat world of modern-day law firms.

Cravath’s change leaves just one or two large firms with what is known as a pure lockstep compensation model, which rewards partners based on the number of years they have worked, regardless of how much business they bring into the firm.