Stock Split:
A corporate action in which a company divides its existing shares into multiple shares. Although the number of shares outstanding increases by a specific multiple, the total value of the shares remains the same compared to pre-split amounts, because the split did not add any real value. This is also known as a "forward stock split."
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Bonus:
A bonus share is a free share of stock given to current shareholders in a company, based upon the number of shares that the shareholder already owns. While the issue of bonus shares increases the total number of shares issued and owned, it does not change the value of the company. Although the total number of issued shares increases, the ratio of number of shares held by each shareholder remains constant.