The near $1 trillion chunk of exchange-traded funds known as smart beta has got a problem: Some of the most popular don’t seem that smart.

More than $14 billion this year has flooded into five of these quant strategies, which are wrapped up in an ETF in a bid to blend active and passive investing. Yet about $5 billion of this went to funds that barely deviate from the stock market, according to Bloomberg Intelligence. The smart-beta products with the purest exposures to systematic factors actually lost cash.

The implications of this multi-year trend could be major for an industry that’s swelled to a fifth of America’s $4.4 trillion ETF market. Legions of investors may not be getting the diversification they’re paying for, while those who are sour on the smartest funds as key strategies misfire.

It highlights the headwinds providers face as they struggle to convince investors to ditch cap-weighted benchmarks and adopt next-generation products.

“The flows basically show investors are hesitant to take on large concentrated bets,” said Athanasios Psarofagis, an analyst at Bloomberg Intelligence. “It’s a balance between picking a product that’s more true to the craft versus what’s easier to fit into a portfolio.”

Born from the work of Nobel laureates and pitched by the biggest firms on Wall Street, smart-beta funds are an attempt to capture potential excess returns by following academically proven quantitative strategies.

Where index ETFs weight companies by their market capitalization, a smart-beta version would typically select and weight constituents based on factors such as profit growth or relative cheapness.