The article discusses why people tend to sell their successful investments too soon and hold onto their losing investments for too long. The researchers suggest that this behavior is influenced by factors like mental accounting, fear of regret, self-control, and tax considerations. They found that tax considerations alone cannot explain this behavior, but when combined with the other factors, they provide a better explanation. The researchers also discovered that the tendency to sell investments at a loss in December is not entirely rational, but aligns with their proposed theory.