Share capital

A corporation's share capital or capital stock (in US English) is the portion of a corporation's equity that has been obtained by the issue of shares in the corporation to a shareholder, usually for cash. "Share capital" may also denote the number and types of shares that compose a corporation's share structure.
In a strict accounting sense, share capital is the nominal value of issued shares (that is, the sum of their par values, sometimes indicated on share certificates). If the allocation price of shares is greater than their par value, as in a rights issue, the shares are said to be sold at a premium (variously called "share premium", "additional paid-in capital" or "paid-in capital in excess of par"). Commonly, the share capital is the total of the aforementioned nominal share capital and the premium share capital. Conversely, when shares are issued below par, they are said to be issued at a discount or part-paid.
Sometimes, shares are allocated in exchange for non-cash consideration, most commonly when corporation A acquires corporation B for shares (new shares issued by corporation A). Here the share capital is increased to the par value of the new shares, and the merger reserve is increased to the balance of the price of corporation B.
In practice, the concept of "par value" has very little meaning, since shares usually represent a residual claim; they do not endow their owners with a claim toward any fixed sum of money. In some jurisdictions, share par values have been either abolished or made optional, so a corporation can issue shares having no par value. In that case, from an accounting perspective, all of the corporation's share capital is premium.
Besides its meaning in accounting, described above, "share capital" may also describe the number and types of shares that compose a corporation's share structure. A corporation might have an "outstanding share capital" of 500,000 shares (the "structure" usage); it has received for them a total of 2 million dollars, which is the "share capital" in the balance sheet (the accounting usage).
The legal aspects of share capital are mostly dealt with in a jurisdiction's corporate law system. An example of such an issue is that when a company allocates new shares, it must do so without inequitably diluting its existing shareholders.
Legal capital.
Legal capital is a concept used in UK company law, EU company law, and various other corporate law jurisdictions to refer to the sum of assets contributed to a company by shareholders when they are issued shares. The law often requires that this capital is maintained, and that dividends are not paid when a company is not showing a profit above the level of historically recorded legal capital.
Minimum capital.
In the UK, a public limited company must have a minimum legal capital of £50,000. There is no such requirement for a private company.
Classes of shares.
The share capital may be made up of more than one class of shares. Different classes of shares include ordinary shares, preference shares, growth shares and deferred shares. Shares will be a separate class if the rights attached to them differ from the rights attached to other shares in the capital of the company.