The charter capital of a joint-stock company is composed of the nominal value of all issued shares. It determines the minimum amount of assets guaranteeing creditors' interests and serves as the basis for calculating shareholders' equity stakes.
Changes are possible in two ways: increase through issuing additional shares or raising their nominal value; decrease through redemption of shares or lowering nominal value. Increasing through additional issuance dilutes existing shareholders' stakes if they don't participate in the placement.
Charter capital should not be confused with equity capital. The former is a fixed amount recorded in the charter; the latter also includes retained earnings, reserves, and revaluation, changing after each reporting period. For long-established companies, equity capital typically exceeds charter capital many times over.
For an investor, charter capital itself is not very informative as a business size indicator. Its practical value lies in calculating stakes: a shareholder's charter capital stake determines their voting rights and claim on assets.