ETF flows on the Charles Schwab brokerage platform reveals increasing demand for the investment vehicle.

ETF assets at Schwab rose to $380 billion in September, compared to $292 billion at the end of the same month last year,  or an overall 12-month increase of 30%.

Registered Investment Advisor clients saw the greatest year-over-year demand, with ETF assets rising to $201 billion from $154 billion, or a 31% increase from last September. Meanwhile, retail investors at Schwab held $132 billion, compared to $104 billion a year ago, or a 27% rise. Lastly, retail traders held $47 billion at Schwab from $34 billion last year, or a 37% increase.

Related: 3 Best & Worst Performing ETFs 2017 YTD

Looking at 12-month ETF flows at Schwab, retail investors experienced the greatest percentage increase in demand for ETFs, rising to 42% for the one-year period ended September 2017, compared to a 35% increase for the one-year period ended September 2016. In contrast, ETF usage among retail traders on the Schwab platform rose to 9% in the year ended September 2017, compared to 5% in the year ended September 2016. Meanwhile, ETF usage among RIA clients at Schwab slipped to 49% in the year ended September 2017, compared to 60% in the year ended September 2016.

Third quarter 2017 flows were $10 billion, contributing to 12-month flows through September 2017 of $46 billion, or up 64% compared to the preceding 12-month period ended September 2016. Among the most popular asset categories of Q3 2017, U.S. fixed income attracted $3.9 billion, international equity saw $3 billion in inflows and U.S. equity added $1.5 billion.

There are now 2,041 U.S.-listed ETFs on the market with $3.2 trillion in assets under management. The U.S. ETF industry has brought in $374.4 billion in net inflows.

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