When to sell your stocks

Investors usually dislike gambling comparisons. Yet at a recent conference held by Norges Bank Investment Management, which oversees Norway’s oil fund of $1.6trn, a packed hall sought to learn from a former poker pro. Annie Duke was there to talk about quitting decisions, a topic on which she wrote the book (“Quit: The Power of Knowing When to Walk Away”). Ms Duke argued that many factors stack the deck against people considering quitting, pushing push them to act irrationally. That applies to poker players wondering whether or not to fold—and also to investors considering whether to exit a position.