The highest-profit firms in the Am Law 50 are pushing the industry toward one of its strongest years in recent memory. But while putting up "admirable" gains in revenue and profits, Second 50 firms are trailing both their larger and smaller counterparts in each category of growth at the halfway mark of the year, according to recent bank data.

There's more than one cause. But relative to the top 50, lower billing rates, more head count, and slowed collections have all contributed to the Second 50′s slower growth. The top 50′s ability to pay a premium for talent and focus on more lucrative practices this year, like capital markets, also matters.