When a company declares a stock split, the price of the stock will decrease, but the number of shares will increase proportionately. For example, if you own 100 shares of a company that trades at $100 per share and it declares a two for one stock split, you will own a total of 200 shares at $50 per share after the split. A stock split has no effect on the value of what shareholders own. If the company pays a dividend, your dividends paid per share will also fall proportionately.
Companies often split their stock when they believe the price of their stock exceeds the amount smaller individual investors would be willing to pay for the stock. By reducing the price of the stock, companies try to make their stock more affordable to these investors.
Although many stock splits are two for one, companies can split their stock in any number of ways, including three for one, three for two, and so forth.
It could be an indicator that a particular stock is doing well.