We’re forever blowing bubbles
Alan Greenspan may say it is "very difficult to definitively identify a bubble until after the fact" but the study of bubbles is far older than he is. This year is the 150th anniversary of the classic text on manias, financial or otherwise: Charles Mackay's Extraordinary Popular Delusions and the Madness of Crowds.
Mackay's study of the South Sea Bubble of 1720 is particularly relevant to central bankers. During that mania, Mackay writes, "visions of boundless wealth floated before the eyes of the people", and half the nation turned stockjobbers. Exchange Alley, the lane near Lombard Street in the City of London where stockjobbers gathered, was at one point so full of citizens mad for South Sea Company shares that the price at one end of the lane was 10% higher than at the other.
Numerous unscrupulous schemes cashed in on investor credulity - one man, who would surely be a dot com entrepreneur were he alive today, set up a joint-stock company "for carrying on an undertaking of great advantage, but nobody to know what it is".