A proportionate increase in the number of shares of outstanding stock without a corresponding increase in assets or in funds available, as would be the case in a new stock offering or in an acquisition that uses stock as payment. Essentially, a firm splits its stock to reduce the market price and make the shares attractive to a larger pool of investors. A 4-for-1 split would result in an owner of 100 shares receiving 300 additional shares, or an after-split total of 4 shares for every 1 share owned before the split. Also called stock split. Compare reverse stock split.