Rising to the partnership ranks at major law firms has traditionally required a range of skills that includes a tireless work ethic, a sharp legal mind and often the potential to bring in new business. One thing that seems increasingly unnecessary for those intent on making partner — unwavering loyalty to the firm that hires them out of law school.

An analysis of new partner classes at 50 Am Law 200 firms shows nearly 59 percent of the 499 associates and counsel promoted at those firms began their career elsewhere. Some logged time in government jobs. Many followed partners making lateral moves. Still others traded positions at firms where the odds of rising were slim to those that offered greater opportunities.