Just For Thinking ...
Over the last few years of reading so many investing blog postings and chatting in cboxes and forums; Uncle8888 has realised many retail investors are more likely to sell their best winning stocks when market turns bearish and then later "re-invest" into other stocks as it is not easy to buy back their best winning stocks due to Anchoring Effect of their last purchase price.
Their other stocks are free from Anchoring Effect so it is easier to find them as replacement stocks. But, their best winning stocks sold may prove to be the best when market finally recovers at the next market cycles......