Focus Financial Partners, the consolidator that went public last summer, led a record first quarter for deals involving registered investment advisors. There were 49 mergers and acquisitions involving RIAs in the first quarter, the highest volume in any three-month period since Echelon Partners, a Los Angeles-based investment bank and consulting firm focused on wealth and investment managers, began keeping track in 2013. Focus and its affiliated firms accounted for 11 of those deals, a quarterly high for the firm. Deals exclusively between RIAs tallied 17 in the first quarter, or about a third of the total.