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.

Financial firms’ adoption of client-facing digital planning and asset allocation tools are also responsible for some of the flows, says Polefrone.

“Independent broker-dealers are adding robo-advisors for smaller accounts and for millennial-type investors,” Polefrone says. “That’s the kind of product that lends itself to more ETFs and passively managed funds because they focus more on fee structure.”

Net new flows for long-term mutual funds increased by 1.2 percent, or $84.7 billion, to $7.4 trillion of assets from third-party financial intermediaries. Of that total, $30.6 billion, or 36 percent of the increase, came into passively managed mutual funds.

RIAs, which already have 33 percent of their assets in passively managed products, experienced virtual no change in total mutual fund assets in the first half of 2016 and a 2.4 percent increase in ETF net new assets.

Polefrone says that RIAs proportionately lower flows into passive products are mostly due to their early adoption of index mutual funds and ETFs.“They have been making this move over a longer period, so there hasn’t been as big a move for them on a percentage basis.”

Discount brokerages, another channel which pioneered passive products, were also up slightly in net mutual fund and ETF assets. Discount brokerages like Schwab and Vanguard account for 55 percent of the assets held in passive products.

The wirehouse channel is beginning to follow RIAs and independent brokerages into passive products, albeit slowly. According to Broadridge, $21 billion of wirehouse assets flowed out of actively managed funds, but assets in passively managed funds and ETFs increase by just $5.2 billion. As a result, wirehouses experienced net outflows of long-term funds of $13 billion in the first half of 2016, losing overall market share to other retail channels.

“It appears that they are losing advisors and clients to RIAs, which are growing significantly, or to independent broker-dealers, which continue to chug along,” Polefrone says.

Net new assets of passive products for the retail channels increased across categories like U.S. large-cap equities, U.S. mid-cap equities, and U.S. fixed income, while net new assets of active products increased across U.S. fixed income, high-yield income and U.S. municipals. Net new assets of active products decreased for U.S. large-cap equities, U.S.mid-cap equities and U.S. small-cap equities.

“We’re seeing an upward movement in passive, core, U.S.-based products, and a downward outflow in their active counterparts,” Polefrone says. “It seems to be a repositioning. At the same time, in fixed income, there are certainly those who believe that active management still works best.”

All told, net new assets of ETFs for retail channels were up by $61.3 billion in the second quarter of 2016, while they declined by $30.4 billion for institutional channels.

Broadridge collects sales and asset data for more than $9 trillion of long-term mutual fund and ETF assets across a majority of mutual fund distributors.