The S&P 500 SPX – 3.88% is in a bear market. History says it will probably get worse before it gets better, but investors who dive in now could profit nicely in the long run.

With the close on 13 June at 3749.91, the index has completed a 20% decline from its recent peak. While it may be tough to look on the bright side when faced with another sea of red on their screens, an examination of past bear markets shows there is good news and bad news for investors once the S&P 500 has crossed that symbolic threshold.