Shares, also known as stock or equity, represent ownership in a corporation or a company. When a company issues shares, it is raising capital by selling a piece of ownership in the company to investors.

Shares are traded on a stock exchange, such as the London Stock Exchange, where their value is determined by supply and demand. The value of a share is based on the overall performance and prospects of the company, as well as broader economic and market conditions.

Shares can be of different types, such as common stock or preferred stock, each with its own set of rights and characteristics. Common stock represents ownership in a company and typically gives the shareholder the right to vote at shareholder meetings and to receive dividends. Preferred stock is a type of share that typically pays a fixed dividend and has priority over common stock when it comes to the distribution of assets if the company is dissolved.

Individuals, institutions, and other companies can own shares and the distribution of shares among the shareholders is known as shareholder structure or shareholding structure. The largest shareholders are often referred to as "insiders" and they have significant influence over the company's management and strategic decisions.

As a shareholder, one can also be referred to as an equity holder. Shareholders also 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.