For over 30 years, market participants have used the Cboe Volatility Index (VIX^®) to gauge expectations for future volatility and measure short-term market sentiment. Today, VIX is a world-renowned measure that was linked to over USD 1 trillion in listed trading activity in 2023. However, it does not encompass all the risks in U.S. equities, or all the opportunities. For instance, if half of the S&P 500^®’s constituents decline precipitously while the other half rise correspondingly, the benchmark may not change much due to diversification effects. Individual stocks exhibit distinct risk profiles compared to the index, and that can be particularly important when navigating around major market events – such as a U.S. election.

On Nov. 4, 2024, a new index, the Cboe S&P 500 Constituent Volatility Index (VIXEQ), was launched through a collaboration between S&P Dow Jones Indices and Cboe. A complementary measure reflecting single-stock risk in the S&P 500, VIXEQ uses options on S&P 500 constituent stocks and VIX’s methodology to build a one-month measure of expected volatility for each constituent; with index level equal to the capitalization-weighted, root mean square average of the single-stock VIX calculations.¹Exhibit 1 shows the current VIX levels for the stocks included in the calculation at the end of the first day of VIXEQ’s publication and Exhibit 2 shows the hypothetical (that is, back-tested) levels of the index since 2014.

(Click on image to enlarge)

VIXEQ’s launch may be particularly timely, because its inaugural closing level provides a concrete example of the kind of unique information it provides, in this case regarding the potential market reaction to the upcoming results of the U.S. presidential election. Specifically, Monday’s VIXEQ index level of 36.77, as compared to a VIX level of 21.98 suggests that, as well as overall moves in the S&P 500, there might be a significant mix of “winners” and “losers” among the benchmark’s constituents over the next 30 days.

To test whether this information might have been useful historically, we² ran a basic case study on the five U.S. election periods included in Exhibit 2—the presidential elections of 2016 and 2020, as well as the Congress and Senate elections in 2014, 2018 and 2022.  Comparing the levels of “implied” and “realized” volatilities, VIX proved a poor predictor: the average realized S&P 500 index volatility in the month after the election day was on average over 8 points different from what VIX anticipated.But while VIXEQ was also far from perfect, it was less inaccurate: on average, just 3 points different from the subsequent (weighted) average S&P 500 single stock volatility.  If that (admittedly small) sample is representative, we might expect individual stock movements to be relatively amplified over the next 30 days, both compared to historical norms and compared to the S&P 500’s concurrent fluctuations.

Of course, uncertainties remain regarding election outcomes and corresponding market reactions.But indices like VIX and VIXEQ, as well as the related DSPX index for implied S&P 500 dispersion, offer valuable insights into market sentiment and the distribution of risks across individual stocks and shared market factors.

¹ There are not quite sufficiently many liquid options on all the S&P 500’s constituents to build a VIX for every stock; instead, a subset of 86 stocks with particularly liquid options markets (precisely, the current constituents of the Cboe S&P 500 Dispersion Basket Index) are used.

² The author is grateful to Will Kennedy for producing analysis and data underlying this post.

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