RIA firms with $1 billion or more under management now control 60 percent of the market, according to new research from Cerulli Associates.

The Boston-based research firm counts 687 “retail-focused” billion-dollar RIA firms that collectively manage $2.4 trillion. For the sake of comparison, ten years ago a good-sized wirehouse branch office had about $1 billion in AUM.

These select firms make up just 3.8 percent of all retail firms, despite handling more than half the assets in the RIA channel.

Since 2012, billion-dollar RIA firms have accumulated market share by attracting big teams from other channels and engaging in a significant amount of merger and acquisition activity, said Marina Shtyrkov, a research analyst at Cerulli, in a statement.

At the same time, the majority of RIA firms have less than $100 million in assets, Shtyrkov said.

Cerulli expects the dominance of larger firms to continue, as they increasingly look to add talent and scale.