STOCK MARKET AND THE VIX

The jump in the stock market indices this week may be explained by a news item on April 18th:
The CBOE Volatility index recently hit its highest level of the year, just above 16, as global geopolitical concerns pressure the markets, sending the S&P 500 sliding modestly toward the end of last week. This may signal a prime buying opportunity, according to Oppenheimer's head of technical analysis, Ari Wald, who points to an intriguing relationship between the market's moves and spikes in the VIX.*

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Perhaps the following figure,** shows the relationship better, but uses the same information from Ari Wald::

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Both references come to the same conclusion.

* http://www.cnbc.com/2017/04/18/since-1990-market-gains-double-when-this-happens--and-it-just-did.html
** http://thereformedbroker.com/2016/06/19/chart-o-the-day-buying-on-vix-spikes/