The mutual fund indexing trend that dominates the market today — and has enjoyed a $1 trillion swing in investor preferences away from managed mutual funds — is a decades-old innovation credited to Malvern-based Vanguard Group founder John Bogle, but the “father of indexing” isn’t too keen on the next generation of indexing innovations, according to a Barron’s video interview on The Wall Street Journal (below).

“It’s not that indexing is smart, … but the cost makes a huge difference in returns, particularly over the long run,” he said in the video.

But newer innovations, like exchange-traded funds (ETFs), don’t measure up through Bogle’s long-term investment lens.

“The ETF is certainly the greatest marketing innovation of the 21st century. I don’t think it’s the best investment innovation,” he said in the video, labeling ETFs instead as a trading strategy, not a long-term investing strategy.

Hear more about Bogle’s views on indexing, ETFs, fiduciary duty and an investment tax in the Barron’s interview on The Wall Street Journal here.