Earnings

• Nothing moves a stock price like its quarterly earnings report. These updates provide the insight investors need about a company's financial health. Simply put, if the report is good, the stock is likely to rise. If it is bad, investors are likely to sell the stock, sending the price down.
  
  

Analyst Ratings

• Most large and medium-sized companies have a group of analysts from various brokerage firms that track the company's performance and expectations. These analysts issue ratings such as "buy," "hold" or "sell," and a change in rating from a well-respected analyst can move a stock's price.
  
  

Share Buybacks

• If a company announces that it is going to repurchase its own stock, this is typically a sign that the executives believe in the stock's long-term value. Share buybacks also reduce the number of shares in the public marketplace, which can help boost quarterly per-share profits, so buybacks usually move a stock up.
  
  

Dividends

• Increasing a dividend or paying one for the first time indicates that a company is financially sound and has the extra cash to reward shareholders. This is a bullish sign. The reduction or elimination of dividend can lead investors to sell the stock, sending its price down.
  
  

Mergers and Acquisitions

• Buyout news always moves the stock of the companies involved. The stock of the company doing the buying usually moves down on the day of the announcement, and the stock of the company to be acquired goes up.