Half of the S&P 500's strongest days over the past 20 years occurred during bear markets, and an additional 34% happened in the early stages of bull markets before they were officially recognized.
"in the event we hit a bare Market that half of the S&P 500's strongest days in the last 20 years occurred during a bare Market and another 34% of the Market's best days took place in the first 2 months of a bull market before it was clear that a bull market had even begun"