A shareholder, also known as a stockholder, is an individual or organization that owns shares of stock in a company. Shareholders are the owners of the company and have a claim on part of the company's assets and earnings.

When a company issues stock, it is selling ownership in the company to shareholders in exchange for capital. In return for their investment, shareholders are entitled to a share of the company's profits and assets. They are also entitled to a share of the company's decision-making power through the right to vote on certain matters such as the election of the board of directors and certain major business decisions.

Shareholders have the potential to earn a return on their investment through dividends, which are a portion of the company's profits that are distributed to shareholders, and capital appreciation, which is an increase in the value of the shares. However, shareholders also bear the risk that the company may not perform as well as expected and the value of their shares may decrease.

The number and type of shareholders a company has can vary widely. A company can have a few large shareholders who own a significant portion of the company's stock or it can have a large number of small shareholders. Additionally, shareholders can be individuals, institutions such as banks or mutual funds, or other companies. It's important for shareholders to keep informed about the company's performance and decisions, and to stay informed of changes in company's regulations and laws that may affect the value of their shares.