Has anybody heard of Skew Index ?
Skew Index is a risk measure (quite different from the popular VIX index) published by CBOE. Without details (for those interested the details are here) this index measures the risk of a very rare market event, e.g. stock market crash or another black swan event. Let us look at the chart:
source: CBOE and Simple Digressions
Look carefully at the blue spikes of the SKEW index. During the on-going bull market, shortly after SKEW index spikes the relevant corrections took place. Presently the SKEW index value is around 130 - it is a very high reading meaning a very high probability of the spectacular event.