Investors might want to bet on Rollins (NYSE: ROL), as it has been recently upgraded to a Zacks Rank #2 (Buy). An upward trend in earnings estimates -- one of the most powerful forces impacting stock prices -- has triggered this rating change. A company's changing earnings picture is at the core of the Zacks rating. The system tracks the Zacks Consensus Estimate -- the consensus measure of EPS estimates from the sell-side analysts covering the stock -- for the current and following years. Individual investors often find it hard to make decisions based on rating upgrades by Wall Street analysts, since these are mostly driven by subjective factors that are hard to see and measure in real time. In these situations, the Zacks rating system comes in handy because of the power of a changing earnings picture in determining near-term stock price movements. Therefore, the Zacks rating upgrade for Rollins basically reflects positivity about its earnings outlook that could translate into buying pressure and an increase in its stock price. Most Powerful Force Impacting Stock Prices The change in a company's future earnings potential, as reflected ...