Finding the Active in Low-Cost Passive Investing

There are any number of ways to construct an index. Some lead to more trading than others, increasing expenses.

Hold them down.

Photographer: Jay Mallin/Bloomberg

I have long defended the idea that a substantial portion of your investable assets should be in a portfolio of low-cost, global, passive indexes. My primary beef with much of the active universe (especially hedge funds and private equity, and the pensions and endowments that love them) is the one-two punch of high expenses and underperformance. And if you are going to pick stocks as an active investor, then be active -- don’t be a closet indexer. Otherwise, you might as well buy a low-cost index fund and be done with it.

There have been some legitimate criticisms raised about the huge and sudden rise of indexing, as well as some foolish critiques. No, passive investing is not "worse than Marxism." 1  No, Vanguard Group Inc. isn't a "nonprofit socialist enterprise." Passive isn't a bubble; it isn't destroying price discovery; it isn't hurting the economy, ruining the market or investing; it's not even (yet) putting security lawyers out of work.

However, passive, low-cost, index-based investing isn't truly, objectively passive. It involves some decision-making, mostly choices that were made in the past by others. Modern passive investors merely default to these earlier decisions. That doesn't make the historical legacy any less active, but it helps to understand the reasons behind these past choices: They were made for purposes of convenience, cost and efficiency.

First, consider the passive equity indexes. These were created using market capitalization weighting long ago; they could just have easily been equal weighted. 2   Cap weighting was the choice made by Vanguard founder Jack Bogle 41 years ago when he introduced the initial Vanguard 500 Index Fund, which was designed to track the performance of the Standard & Poor's 500 Index. His thinking: It was the cheapest way to construct and manage an index.

He had other choices. He could have selected equal weighting. However, price changes of each individual security would have quickly moved the index away from equal weight. Maintaining equal weighting of the 500 stocks in the S&P 500 would have required regular rebalancing -- perhaps as often as quarterly or even monthly -- driving up trading costs. It is easy to see why Bogle went with cap weighting.

That also leads to the S&P 500 itself: Why rely on the assessment of S&P to come up with 500 names? Why not simply take the 500 biggest publicly traded companies and save money on licensing the index from S&P? The S&P index methodology explains how it selects companies, mostly relying on market value. But other factors enter into the calculation. First, S&P distributes the stocks across 11 industrial sectors. But it also looks at issues of liquidity and public float, as well as home domicile.

Had Bogle gone with pure market-cap weighting, it would have run the risk of over-exposure to a specific sector that became hot quickly. Just imagine what a pure S&P 500 cap-weighted index would have looked like in 1999 near the peak of the dot-com bubble.

The new wave of fundamental indexes, also known as smart beta, is another alternative to cap-weighted indexes. A stock index could easily have been weighted by revenue -- that is how the Fortune 500 is constructed. There are many choices available to anyone who wants to create an index from scratch. Dividend yield, profit growth, price-to-earnings -- but the same criticism is that these other methods of weighing an index will result in more rebalancing and trading, and therefore higher expenses. The bottom line is that cap-weighting seems to always win the low-cost argument.

What I find to be the most intriguing criticism of passive indexing comes from looking at an asset allocation portfolio as a whole: Typical portfolios don't accurately reflect the weight of investable asset classes around the world. I am not referring to home country bias, but rather the relative weightings of stocks, bonds commodities and real estate in a portfolio.

The global real estate market -- land and improvements --- is more than $200 trillion, public debt is $95 trillion, private loans (securitized or not) is $99 trillion, equity is $67 trillion, cash and equivalents is $41 trillion. 3  Most portfolios obviously look nothing like this. The classic 60/40 (or 70/30) blend of stocks and bonds doesn't reflect real-world asset sizes. However, it is a reflection of Harry Markowitz's modern portfolio theory, which considers risk relative to expected returns. Any indexer must also plead guilty on that count.  

Hence, passive does reflect a number of choices, made over time. This is why some of the pioneers of indexing -- Charlie Ellis, former chairman of the Yale University endowment, comes to mind -- prefer the phrase "low-cost indexing” rather than passive investing. You should, too.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

  1. I don’t like to go ad hominem, but how historically unaware does one have to be about the evils of communism before publishing something like that?

  2. A global list of 500 market-cap-weighted companies is the FT 500.

  3. Sources: CFA Institute and Europroperty. Closely held businesses, perhaps a proxy in part for alternatives like private equity and venture capital, is another $100 trillion.

To contact the author of this story:
Barry Ritholtz at

To contact the editor responsible for this story:
James Greiff at

Before it's here, it's on the Bloomberg Terminal.