Here's what happened during the last 10 US bear markets

As the old saying goes, "Those who cannot remember the past are condemned to repeat it."

JP Morgan's review of global markets and economies included a look back at the past ten bear markets in US history, dating back to the Great Depression. To qualify, S&P 500 had to drop 20% off the all-time high.

Looking at the slide, there are some themes that pop out. Maybe most obviously, 8 of the 10 were accompanied by recessions as defined by the National Bureau of Economic Research. The three main hallmarks JP Morgan observed - commodity spikes, aggressive Fed tightening and extreme valuations - each occurred four times over the 10 bear markets and only once, the 1987 crash, bore none of those hallmarks.

Commodity spikes (defined as "significant rapid upward move in oil prices") and aggressive Fed tightening ("monetary tightening that was unexpected and significant in magnitude") occurred together 3 times and is what JP Morgan cites as conditions during the 2007 Global Financial Crisis.

While it may simplify broad economic situations, the chart provides an intriguing snapshot of when and why US markets meltdown.

JP Morgan Asset Management