Vertical Integration and the Theory of the Firm
Authors: Kim Jongwook 
Published: September 2018

How do firms organize economic transactions? This question can be thought of as a question of firm boundaries or as a decision about a firm’s scope, encompassing the choice along a continuum of governance structures, including spot markets, short-term contracts, long-term contracts, franchising, licensing, joint ventures, and hierarchy (integration). Although there is no unified theory of vertical integration, transaction cost economics, agency theory, and more recently property rights theory have been influential not only in analyzing make-or-buy decisions but also in understanding “hybrid forms” or inter-firm alliances, such as technology licensing contracts, equity alliances, joint ventures, and the like.

Before Coase’s work became widely known, whatever theoretical underpinnings there were of vertical integration were provided by applications of neoclassical theory. Here, the firm was viewed as a production function that utilized the most technologically efficient way to convert input into output. In particular, neoclassical theory was concerned primarily with market power and the distortions that it created in markets for inputs or outputs as the main driver of vertical integration. Hence, the boundaries of the firm—that is, where to draw the line between transactions that occur within the firm and those outside the firm—were irrelevant within this framework. It was Coase’s question “Why is there any organization?” that first suggested that price mechanisms in the market and managerial coordination within firms were alternative governance mechanisms. That is, the choice between these alternative mechanisms was driven by a comparative analysis of the costs of implementing either mechanism.

Oliver Williamson built on Coase to provide the theoretical foundations for vertical integration by joining uncertainty and small numbers with opportunism in defining exchange hazards, and consequently established comparative analysis of alternative governance forms as the way to analyze vertical integration. More recently, property rights theory brought attention to ownership of key assets as a way to distinguish between the governance of internal organizations and those of market transactions, where ownership confers the authority to determine how these assets will be utilized. And lastly, agency theory also provides important building blocks for understanding contractual choice by placing the emphasis on the different incentives that vary with different contractual arrangements between a principal and its agent.

Transaction cost economics, property rights theory, and agency cost theory complement one another well in explaining vertical integration in terms of alternative governance forms in a world of asymmetric information, bounded rationality, and opportunism. These theories have also been utilized in analyzing “hybrid” organizational forms, in particular strategic alliances and joint ventures. Together, vertical integration and alliances account for a significant part of corporate strategy decisions, and more research on the theoretical foundations as well as novel ways to apply these theories in empirical analyses will be productive avenues for a better understanding of firm behavior.