FEB. 16, 2017 – Today the CBOE SKEW Index rose to 141.41, its highest level this month, and its 25th highest value since January 1990. With U.S. stock market indexes recently hitting all-time highs, there is quite a bit investor uncertainty about the markets and there is high demand for protection from large market declines. In the 27 years from 1990 through 2016, the average daily level for the SKEW Index was 118.4, and the average level of SKEW never topped 130 in any of those 27 years. In the year 2017 (through February 16) the average daily level of the SKEW Index was a relatively high 132.2, which could indicate increased relative demand for use of out-of-the-money SPX put options for portfolio protection.
CBOE SKEW Index values, which are calculated from weighted strips of out-of-the-money S&P 500 options, rise to higher levels as investors become more fearful of a “black swan” event — an unexpected event of large magnitude and consequence. The value of SKEW increases with the expected tail risk of S&P 500 returns. If there were no tail risk expectations, SKEW would be equal to 100. Historically, SKEW has varied in a range of 100 to 147 around an average value of 115.
The FAQ on the CBOE SKEW Index notes that –
“The price of S&P 500 skewness is inconvenient to use directly as an index because it is typically a small negative number, for example -.8, -2.3, or -4.3. SKEW converts this price as follows: SKEW = 100 – 10 * price of skewness. With this definition, a price of -2.1 translates to a SKEW value of 121. S&P 500 options with 30 days to expiration are generally unavailable. SKEW is therefore interpolated from two “SKEW” values at the maturities of nearby and second nearby options with at least 8 days left to expiration.”
For more information please visit www.cboe.com/SKEW.