Mark Hulbert writes in MarkWatch: “not infrequently, a bear-market declaration often amounts to little more than closing the barn door after the horses have left.” A bear market is typically defined by a 20% or greater decline in stock prices. In the last U.S. bear market (2011), for example, “the early-October day when the S&P 500 fell to 20% below its late-April high turned out to be the day that the bear market breathed its last gasp.” Because the average length of a bear market since 1900 is 403 days, “even if it is eventually determined that a bear market began last June, if it’s no worse than average it’s already more than half over.”