Federal Reserve chairman Alan Greenspan, whose death was announced on Monday night, was an icon of the financial world for many reasons. But in 1996, he gave markets a phrase that will live on forever: irrational exuberance.It’s a wonderfully elegant way to describe those periods when investors lose their heads. And we’re living through one now.Subscribe to gift this articleGift 5 articles to anyone you choose each month when you subscribe.Subscribe nowAlready a subscriber? Fetching latest articles