Those pining for a bottom to the gut-wrenching stock market selloff may be disappointed to learn that mega one-day rallies like the historic one witnessed on Tuesday are typically not the start of a durable recovery. All the same, data suggest investors should treat the rally in stocks with caution. Of the twenty past instances when the S&P rallied 8% or more on a single day, thirteen of them took place when stocks were in the embrace of a bear market.