Investors might want to bet on RLI Corp. (NYSE: RLI), as it has been recently upgraded to a Zacks Rank #1 (Strong Buy). This rating change essentially reflects an upward trend in earnings estimates -- one of the most powerful forces impacting stock prices. The sole determinant of the Zacks rating is a company's changing earnings picture. The Zacks Consensus Estimate -- the consensus of EPS estimates from the sell-side analysts covering the stock -- for the current and following years is tracked by the system. 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 RLI Corp. 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 ...