We are believers in low volatility, just not at any price.
Recently, low- or minimum-volatility ETFs have been all the rage. PowerShares S&P 500 Low Volatility SPLV and iShares MSCI USA Minimum Volatility USMV have combined to attract $9 billion in assets in less than two years since inception. SPLV selects the 100 least-volatile stocks from the S&P 500, and it is touted as a simple way to take advantage of the low-volatility anomaly. However, there is perhaps an even simpler way: mega-caps.
For those of you unfamiliar with the low-volatility anomaly, a short review is in order. In the 1970s, Fischer Black observed that low-beta stocks, which were less sensitive to the broad market's gyrations, performed nearly identically with high-beta stocks. This contradicted a fundamental prediction of the capital asset pricing model, or CAPM, which was that higher beta equals higher returns. A number of more recent studies have shined a light on the anomaly, including "Benchmarks as Limits to Arbitrage: Understanding the Low Volatility Anomaly," by Baker, Bradley, and Wurgler.
This study argues that some investors prefer higher-risk strategies with the biggest potential upside. How else can we explain the popularity of lotteries despite the fact that they are negative net present value investments? Further, institutions such as mutual funds are restricted in the use of leverage but have incentive to beat a benchmark, so they seek out high-risk beta stocks that give the highest potential returns. This results in high-beta stocks being bid up to the point where future returns are lower than expected.
A number of ETFs have come to market to exploit the phenomena. But the recent popularity of low-volatility strategies probably owes to the fact that investors have been exceptionally risk-averse since the financial crisis, and low-volatility strategies held up better during that period. In the four years since the market peaked in October 2007, the S&P 500 lost a cumulative 11% while the S&P 500 Low Volatility Index gained 14%.
In the Land of the Giants
Mega-cap stocks are blue-chip companies, international conglomerates, or firms with strong brands and wide economic moats. These companies are large for a reason. Their industry dominance and diversified revenue streams result in more predictable earnings, which makes their stock prices less volatile. Morningstar defines mega-caps as those in the top 40% of the cumulative market capitalization, which currently puts them at $56.8 billion or greater in market cap. At this cutoff, only about 55 companies would qualify as mega-cap.
There are a number of mega-cap-themed ETFs, including iShares S&P 100 Index OEF, Guggenheim Russell Top 50 Mega Cap XLG, SPDR Dow Jones Industrial Average DIA, and Vanguard Mega Cap MGC. OEF tracks the 100 stocks from the S&P 500 with liquid options markets. XLG tracks the 50 largest companies from the Russell 1000, giving it the highest average market cap at $163.3 billion. DIA tracks the well-known Dow Jones Industrial Average, a price-weighted index of blue-chip companies. MGC is the cheapest option, but the CRSP index it follows dips into large-cap territory, so it has less pure exposure to mega-caps.
Risk and Return
Historically, mega-cap stocks have been somewhat less volatile than the market overall. The S&P 500 has had a volatility of return of 15.4% since 2002, while the Russell Top 50 Index has been somewhat less volatile at 14.8%. While slightly less volatile, mega-cap stocks do not necessarily benefit from the low-volatility anomaly. The Russell Top 50 Index had an annualized return of 3.2% during that period, less than the 4.9% return of the S&P 500. However, the S&P 500 Low Volatility Index had a much lower volatility at only 10.5% and a much higher return at 8.6%. So it seems that a portfolio of stocks built on large size does indeed have lower volatility but does not have the same outperformance as a portfolio built by targeting low-volatility stocks explicitly.