Summary: When it comes to mergers and acquisitions of RIAs, much attention has rightly been given to "rollup" or consolidator firms like Focus Financial, United Capital and Dynasty. But the latest data published Feb. 9 in the Nuveen/DeVoe RIA Deal Book reveals another face of the consolidator trend: sub-acquisitions by those consoiidators’ partner RIA firms accounted for 12% (or 19) of all 142 deals last year, and 22% of established RIA firm transactions in 2016, amounting to a “breakout year for sub-acquisitions." The average size of those acquired RIA firms was over $1 billion in AUM.