Investment interest in exchange traded fund products is on the rise, primarily driven by registered investment advisor clients, according to a Charles Schwab (NYSE: SCHW) study.

According to a Schwab note, RIA clients accounted for 54% of ETF flows over the past year and made up 61% of ETF flows for the third quarter at Schwab. In comparison, RIA clients accounted for 34% of ETF flows in the year ended Sept. 2011. [Study: RIAs Allocating More Assets to ETFs]

Overall interest in ETFs is also on the rise. ETF assets custodied at Schwab were $146 billion at the end of the third quarter, up 35% year-over-year, compared to the 34% growth for the entire industry. [Schwab Study: ETFs Are Here to Stay but More Education Needed]

Schwab also revealed that investors were honing in on sector ETFs – assets in sector ETFs at Schwab have increased 49% over the past year. RIA clients favored equity energy, real estate and global real estate ETFs. Retail investors also leaned toward real estate related ETFs.

On a sector-by-sector basis, global real estate ETF assets attracted the highest inflows, doubling in size so far this year. Financial ETFs also experienced strong asset inflows. On the other hand, consumer defensive and utilities ETFs were the only two categories that did not experience double digit asset growth this year.

For more information on ETF asset flows, visit our ETF performance reports category.

Max Chen contributed to this article.

The opinions and forecasts expressed herein are solely those of Tom Lydon, and may not actually come to pass. Information on this site should not be used or construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any product.