Low-cost, passive investment is apparently contagious.

In the first half of 2016, the accelerating movement of assets from active to passive investments such as index mutual funds and ETFs spread from the RIA channel to independent broker-dealers and wirehouses, according to a recent study.

Lake Success, N.Y.-based Broadridge Financial Solutions released data on Thursday regarding mutual fund and ETF flows from its Fund Distribution Intelligence unit that shows the exodus of assets from active mutual funds is increasing, particularly among broker dealers.

“We know how passive products have become part of the advisor world and how that’s affected by distribution channels,” says Frank Polefrone, senior vice president of Broadridge’s data and analytics business. “The independent broker-dealer channel is following suit, and I even think you’re seeing more wirehouses moving in that direction. As they become more fee-based, these firms are taking asset fees for their advisory services and pricing pressure within products becomes more of an issue.”

According to the report, during the first half of 2016 net new assets for passively managed funds and ETFs increased by 9 percent for independent broker-dealers and by one percent for wirehouses.

From independent broker-dealers, actively managed mutual funds saw $35 billion of net outflows, most of which went into ETFs, which saw net new assets of $34.9 billion from the channel. The shift increased the overall share of ETF products managed at independent broker-dealers from 19.5 percent in 2015 to 21 percent in 2016.

Polefrone attributes some of the asset flows to the impending Department of Labor fiduciary rule, which will begin to be enforced next year.

“This trend really started before the rule was finalized and before people understood what the rule was going to entail,” Polefrone says. “The RIA channels were positioned to deal with it. The broker-dealers are now playing catch-up, and that’s why we saw such a big change for them in the first half.”

Overall net new assets for ETFs increased by 1.2 percent, or $24.8 billion, to $2.2 trillion, in the first half of 2016. Of those new assets, 91 percent, or $22.5 trillion, of the increase flowed into passively managed ETFs.

In the same time period, net new assets for passively managed mutual funds increased by $37 billion, or 14 percent, for retail distribution channels, while actively managed funds were down by $24 billion, or 0.6 percent.