Methodology: The NLJ 500 is the National Law Journal's survey of the 500 largest law firms in the United States covering the previous calendar year. Data is collected from firms at the same time as the Am Law financial numbers. ALM sent surveys this year to more than 900 law firms to determine the 500 largest U.S.-centric firms by headcount. Firms smaller than No. 350 are divided into two tiers instead of earning individual ranks.