The CBOE SKEW Index (SKEW) topped 142 on each of the first four trading days this week. The long-term daily average for the SKEW Index (since January 1990) is 118.8, but the daily average for the SKEW Index in 2017 (through August 17) is a much higher 134.5. CBOE SKEW Index values, which are calculated from weighted strips of out-of-the-money S&P 500 options, often rise to higher levels as investors become more fearful of a “black swan” event — an unexpected event of large magnitude[...]