Voluntary amalgamation of two firms on roughly equal terms into one new legal entity. Mergers are effected by exchange of the pre-merger stock (shares) for the stock of the new firm. Owners of each pre-merger firm continue as owners, and the resources of the merging entities are pooled for the benefit of the new entity. If the merged entities were competitors, the merger is called horizontal integration, if they were supplier or customer of one another, it is called vertical integration.