Are Index Funds Destroying Market Efficiency?

Advisor Perspectives welcomes guest contributions. The views presented here do not necessarily represent those of Advisor Perspectives.

This article originally appeared on ETF.COM here.

Over the past few decades, there has been a substantial shift from active to passive investment strategies. This shift has occurred as investors have become more aware of the persistent failure of active management, as demonstrated in the S&P Dow Jones biannual Indices Versus Active (SPIVA) reports.

A January 2019 Federal Reserve Bank of Boston study, “The Shift from Active to Passive Investing: Potential Risks to Financial Stability?”, found that “Passive funds made up 45% of the assets under management (AUM) in equity funds and 26% for bond funds at the end of 2017, whereas both shares were less than 5% in 2005.”

Wall Street has been attacking and ridiculing passive investing for decades. Among the arguments are that the rise of passive investing results in a reduction in price discovery efforts, leading to prices being distorted and capital allocated inefficiently. This occurs because indexing either has too large an influence on prices or it inhibits price discovery because it lowers aggregate market trading volume.

The great irony is that if indexing’s popularity were distorting prices, active managers should be cheering, not ranting against its use, as it would provide them easy pickings, allowing them to outperform. (Note that if money flowing into passive funds distorts prices, it could still make it difficult for active managers while it is occurring, as distortions could persist as long as the flow continued. Eventually, though, the opportunity would manifest itself.) In reality, the rise of indexing has coincided with a dramatic fall in the percentage of active managers outperforming on a risk-adjusted basis.