This year, the RIA Firm ranking expanded to 40 spots (from 30 last year and 20 in 2016), to make room for the explosive growth of elite firms. The average assets under management by the top 20 RIA firms in our survey grew 40.7% since 2016, to $15.8 billion. Their operations are similarly expanding: The average number of offices rose from 20 to 31; the average number of advisors at each firm grew from 63 to 83; and the average number of advisory clients increased from 5,518 to 8,012.