A four-for-one split means that three shares of stock are issued for each share in existence prior to the split. After the split, each share is worth one-fourth of what it was worth immediately prior to the split.
Here’s an example:
Let’s assume that as of the Record Date (April 3, 2013) an investor owns 100 shares of salesforce.com common stock and let’s also assume that the market price of salesforce.com stock is $180 per share, so the investment in salesforce.com is worth $18,000. Let’s also assume that the stock price doesn’t move up or down between the record date and the time the split actually takes place. Immediately after the split, the investor would own 400 shares of salesforce.com stock, but the market price would be $45 per share. The investor’s total investment value in salesforce.com would remain the same at $18,000 until the stock price moves up or down.