Back before everyone became a junk bond expert, we repeatedly showed what in our opinion was the scariest chart for not only the US, but global stock markets: the unprecedented divergence between the stocks and junk bonds, suggesting that if the recent past is prologue, then the S&P 500 is in for a world of pain as it tracks HY credit far lower.
http://www.zerohedge.com/news/2016-02-01/these-are-still-most-disturbing-charts-stock-market