A stock split or stock divide increases the number of shares in a company. For example, after a 2-for-1 split, each investor will own double the number of shares, and each share will be worth half as much. A stock split causes a decrease of market price of individual shares, but does not change the total market capitalization of the company: stock dilution does not occur.
A company may split its stock when the market price per share is so high that it becomes unwieldy when traded. One of the reasons is that a very high share price may deter small investors from buying the shares. Stock splits are usually initiated after a large run up in share price.
The main effect of stock splits is an increase in the liquidity of a stock: there are more buyers and sellers for 10 shares at $10 than 1 share at $100. Some companies avoid a stock split to obtain the opposite strategy: by refusing to split the stock and keeping the price high, they reduce trading volume. Berkshire Hathaway is a notable example of this. The company has never had a stock split and each share trades at over US$400,000.
Other effects could be psychological. If many investors believe that a stock split will result in an increased share price and purchase the stock the share price will tend to increase. Others contend that the management of a company, by initiating a stock split, is implicitly signaling its confidence in the future prospects of the company.
In a market where there is a high minimum number of shares, or a penalty for trading in so-called odd lots (a non multiple of some arbitrary number of shares), a reduced share price may attract more attention from small investors. Small investors such as these, however, will have negligible impact on the overall price.
Ratios of 2-for-1, 3-for-1, and 3-for-2 splits are the most common, but any ratio is possible. Splits of 4-for-3, 5-for-2, and 5-for-4 are used, though less frequently. Investors will sometimes receive cash payments in lieu of fractional shares.
In the above examples ‘y-for-x’ Shows the number of shares before (x) and after (y). Other common reporting nomenclatures are ‘x-y’ and ‘stock dividend’ of [=]y-x. In the above ‘3-for-1’ example (or 1-3 and 2 share stock dividend) would mean a stockholder holding 100 shares (on record date) will receive 200 new shares after the split for those 100 shares.