The torrent of wirehouse brokers flooding RIAs is slowing.

Breakaway brokers joining RIAs accounted for more than half of all merger and acquisition transactions in 2014, but only 39% of RIA deals for the first half of this year involved breakaways, a mid-year review by DeVoe & Company's RIA Deal Book found.

"The shift is also driven by the expiration of the deluge of seven-year forgivable loans wirehouses made in 2008 and 2009 to retain or entice large broker/adviser teams," says David DeVoe, managing partner of the San Francisco-based consulting and research firm. "As those loans were forgiven in the last two years, we saw a spike in the number of wirehouse advisers who left their employers and often joined established RIAs. But that wave has subsided."

RIA M&A: Fast, furious and record breaking
“We expect this momentum to continue and potentially accelerate over the next five to seven years,” says investment banker David DeVoe.

Through June, established RIAs accounted for 43 transactions, while breakaway brokers were involved in 28 M&A deals. The 71 transactions are keeping pace with 2015's' mid-year activity, which culminated with a record 130 deals, according to the Nuveen-sponsored RIA Deal Book.

In addition, the average size of RIAs being acquired is increasing.

Average AUM of an established seller with AUM between $100 million and $5 billion in 2013 was $649 million. Average assets under management for sellers soared to $1 billion this year —a 54% increase.

Read more: RIA mega-merger — how big is it really?

This steady increase in the average size of sellers reflects the growing size of RIAs in general and "the appetite of deep-pock­eted acquirers that are seeking greater scale in the transac­tions they execute," according to the report. ”We've had two solid years of record activity under our belt, and this week's Tiedemann-Presidio deal is further evidence the trend is continuing," says DeVoe. "This could be the new normal.

“Value and scale are driving deals," he explains. "Size is becoming more important, as regulations and technology options become increasingly complex.”

Charles Paikert

Charles Paikert

Charles Paikert is a senior editor with Financial Planning, a SourceMedia publication.