Vertical integration occurs when a firm does something for itself that it could otherwise procure on the market. For example, a manufacturer that opens its own stores is said to be vertically integrated into distribution. One irony of history is that both classical political economy and neoclassicism saw vertical integration and vertical contractual arrangements as much less threatening to competition than cartels or other horizontal arrangements. Nevertheless, vertical integration has produced by far the greater amount of legislation at both federal and state levels and has motivated many more political action groups. Two things explain this phenomenon. First, while economists prior to the 1930s rarely saw a threat, neither did they understand why firms integrate or enter into long term contracts, except for fairly obvious savings in production costs. Second, vertical integration led to many bankruptcies of small family businesses unable or unwilling to take on the costs and associated risks of integrating vertically themselves. When that happened, politics inevitably triumphed over economics.
Both the common law and classical economists tended to view vertical integration favorably. The principal limitation on vertical integration by contract was common law rules limiting restraints on alienation. The managerial revolution in the United States in the nineteenth century occasioned the rise of significant vertical integration. At the same time, however marginalist, or neoclassical, economics first began to see significant competitive problems. The emergent legal policy toward vertical control by contract was developed first in intellectual property law's "first sale" doctrine, and later on in antitrust policy.
In his 1937 article on the "Nature of the Firm," Ronald H. Coase formulated a purely marginalist theory of vertical integration, but it was ignored by both economists and legal policy makers for nearly half a century. Economists continued to wrestle with theories that were far more myopic, and as a result much less satisfactory. The result was that vertical integration became much more vulnerable to special interest legislation than did competition policy generally. By the mid-twentieth century a set of aggressive antitrust policies had emerged that dealt harshly with both vertical integration by contract and ownership vertical integration.
Hovenkamp, Herbert J., "The Law of Vertical Integration and the Business Firm: 1880-1960" (2010). Faculty Scholarship. 1782.