NEW YORK — Somebody on a bus asks a friend, "How about that stock market?" The response: "Unbelievable." Caribbean vacationers lounging poolside check their Blackberries for stock prices. Suburban gym members chat about the latest market gains during their morning workouts.

Welcome to the 2009 bull market — or so many people think. They’re buying up shares of everything from Google Inc. to Bank of America Corp. at a pace not seen since the 1930s. Since March, the Dow Jones industrial average has jumped 57 percent and the Standard & Poor’s 500 index has gained 62 percent.