This screen finds stocks whose MACD is below zero. The MACD(12,26,9), created by Gerald Appel, is the difference between the 12-day and 26-day exponential moving averages; its 9-day EMA is the signal line, and the zero line marks where the two averages are equal. A negative MACD means the faster average is below the slower one, which describes a stock in a downtrend.