Paul Krugman: Bull Market Blues

Like most economists, I don’t usually have much to say about stocks. Stocks are even more susceptible than other markets to popular delusions and the madness of crowds, and stock prices generally have a lot less to do with the state of the economy or its future prospects than many people believe. As the economist Paul Samuelson put it, “Wall Street indexes predicted nine out of the last five recessions.”

Still, we shouldn’t completely ignore stock prices. The fact that the major averages have lately been hitting new highs — the Dow has risen 177 percent from its low point in March 2009 — is newsworthy and noteworthy. What are those Wall Street indexes telling us?