The Turn of the SKEW

September 01, 2021 | Evan Frazier, CFA, CAIA, Senior Research Analyst

Domestic stock indices have rebounded from pandemic-induced lows exhibited in the spring of 2020 with relative ease, and U.S. equity market volatility has remained largely muted since that time as a result. The CBOE Volatility Index (“VIX”), a popular measure of expected volatility in the S&P 500, ended August at a level of 16.6, below the index’s 30-year average of 19.5. Based solely on recent performance and volatility levels of broad-based indices, the investor outlook for U.S. stocks going forward appears mostly positive. That said, other gauges of sentiment may indicate more discord among market participants. The CBOE SKEW Index (“SKEW”) is one such barometer. Unlike the VIX, which uses at-the-money S&P 500 Index options to assess expectations of near-term market fluctuations, the SKEW examines the implied volatility of out-of-the-money options to gauge perceived U.S. equity market tail-risk, or the chances of an extreme price change in the index. The SKEW Index ended August at a level of 155.9 after reaching an all-time high of 170.6 in late June of this year — both figures are well above the 30-year average for the index of 120.5. The recent upward movement in the SKEW indicates that investors have grown increasingly wary of an outsized move in domestic equity indices in the last several months.

It is important to note that an elevated SKEW Index is not necessarily a harbinger of a tail-risk event. Since 1990, the average 30-day return for the S&P 500 Index subsequent to the SKEW spiking into the 90th percentile of its history was roughly 0.9%. The inverse is also true — extreme S&P 500 returns are not always precipitated by an elevated SKEW Index. In the two years leading up to the Tech Bubble Crash and Global Financial Crisis, the SKEW averaged levels of 115.4 and 116.6, respectively, both of which are below the long-term mean for the index. All of that said, there are obvious risks currently facing markets that could lead to pullbacks and may be contributing to heightened SKEW measures. For instance, valuations of most U.S. equity indices remain elevated relative to historical norms and heightened inflation could ultimately prove less transient than currently expected by market participants. Additionally, the S&P 500 Index has experienced a maximum drawdown of just 4.1% so far this year, well below the median annual drawdown for the benchmark of 9.7% going back 30 years. While this data point alone does not portend a correction, a near-term drawdown is certainly possible given the myriad factors at play. In light of the current landscape, we believe it is imperative for investors to remain diversified across the asset class spectrum in order to gain exposure to a potential continuation of recent positive equity performance while also helping to protect portfolios in the event of a correction.

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