A stock split is used by a corporation usually to reduce the price of a stock so more retail investors can easily purchase the stock. A stock split is usually seen as a very positive event. If a stock say IBM is priced at $120 and you have 100 shares the total value of your holdings will be $12,000. After the split, you will have 200 shares but the price of the stock will be $60. You will still own $12,000 worth of IBM.