||The examples and perspective in this article may not represent a worldwide view of the subject. (December 2010)|
A parent company is a company that owns enough voting stock in another firm to control management and operations by influencing or electing its board of directors; the second company being deemed as a subsidiary of the parent company. The definition of a parent company differs by jurisdiction, with the definition normally being defined by way of laws dealing with companies in that jurisdiction.
Definitions from around the world 
- (a) the other body:
- (i) controls the composition of the first body's board; or
- (ii) is in a position to cast, or control the casting of, more than one-half of the maximum number of votes that might be cast at a general meeting of the first body; or
- (iii) holds more than one-half of the issued share capital of the first body (excluding any part of that issued share capital that carries no right to participate beyond a specified amount in a distribution of either profits or capital); or
- (b) the first body is a subsidiary of a subsidiary of the other body.
5. —(1) For the purposes of this Act, a corporation shall, subject to subsection (3), be deemed to be a subsidiary of another corporation, if —
- (a) that other corporation —
- (i) controls the composition of the board of directors of the first-mentioned corporation;
- (ii) controls more than half of the voting power of the first-mentioned corporation; or
- (iii) holds more than half of the issued share capital of the first-mentioned corporation (excluding any part thereof which consists of preference shares and treasury shares); or
- (b) the first-mentioned corporation is a subsidiary of any corporation which is that other corporation’s subsidiary.
United Kingdom 
In the UK it is generally held that an organisation holding a "controlling stake" in a company (a holding of over 51% of the stock) is in effect the de facto parent company of the firm, having overriding material influence over the held company's operations, even if no formal full takeover has been enacted. Once a full takeover or purchase is enacted, then the held company is seen to have ceased to operate as an independent entity and become a trading subsidiary of the purchasing company, which in turn becomes the parent company of the subsidiary. (A holding below 50% could be sufficient to give a parent company material influence if they are the largest individual shareholder or if they are placed in control of the running of the operation by non-operational shareholders).