Below is a chart showing the rolling 50-trading day correlation between the daily percentage change of oil and the S&P 500 over the last ten years. This allows you to see how closely the two have traded with each other over time. Over the last 6-12 months or so, it has certainly seemed like whichever direction oil was trading that day, the S&P 500 was heading the same way. But in actuality, the correlation between the two has just recently hit a multi-year peak, rising up to 0.6 (1.0 is perfect correlation) as of today. As you can see in the chart, over the last 50 trading days, the two have traded more closely with each other than at any point since early 2013. But 0.6 is not by any means the highest correlation the two have seen over the last ten years. From 2009 to 2012, correlation levels got above 0.7 multiple times.