Investors should also take note of AMPH's average 20-day trading volume. Volume is a useful item in many ways, and the 20-day average establishes a good price-to-volume baseline; a rising stock with above average volume is generally a bullish sign, whereas a declining stock on above average volume is typically bearish. Right now, AMPH is averaging 390,470 shares for the last 20 days. Earnings Outlook The Zacks Momentum Style Score encompasses many things, including estimate revisions and a stock's price movement. Investors should note that earnings estimates are also significant to the Zacks Rank, and a nice path here can be promising. We have recently been noticing this with AMPH. Over the past two months, 2 earnings estimates moved higher compared to none lower for the full year. These revisions helped boost AMPH's consensus estimate, increasing from $2.38 to $2.69 in the past 60 days.