In this paper, we extend the growth model to include firm-specific technology capital and use it to assess the gains from opening to foreign direct investment. A firm’s technology capital is its unique know-how from investing in research and development, brands, and organization capital. Technology capital is distinguished from other forms of capital in that a firm can use it simultaneously in multiple domestic and foreign locations. A country can exploit foreign technology capital by permitting direct investment by foreign multinationals. In both steady-state and transitional analyses, the extended growth model predicts large gains to being open.

A framework is developed with what we call technology capital. A country is a measure of locations. Absent policy constraints, a firm owning a unit of technology capital can produce the composite output good using the unit of technology capital at as many locations as it chooses. But it can operate only one operation at a given location, so the number of locations is what constrains the number of units it operates using this unit of technology capital. If it has two units of technology capital, it can operate twice as many operations at every location. In this paper, aggregation is carried out and the aggregate production functions for the countries are derived. Our framework interacts well with the national accounts in the same way as does the neoclassical growth model. It also interacts well with the international accounts. There are constant returns to scale, and therefore no monopoly rents. Yet there are gains to being economically integrated. In the framework, a country’s openness is measured by the effect of its policies on the productivity of foreign operations. Our analysis indicates that there are large gains to this openness.

Empirical studies quantifying the benefits of increased foreign direct investment (FDI) have been unable to provide conclusive evidence of a positive impact on the host country’s economic performance. I show that the lack of robust evidence is not inconsistent with theory, even if the gains to FDI openness are large. Anticipated welfare gains to increased inward FDI should lead to immediate declines in domestic investment and employment and eventual increases. Furthermore, since part of FDI is intangible investment that is expensed from company profits, gross domestic product (GDP) and gross national product (GNP) should decline during periods of abnormally high FDI investment. Using the model of McGrattan and Prescott (2009) and data from the IMF Balance of Payments to parameterize the time paths of FDI openness for each country in the sample, I do not find an economically significant relationship between the amount of inward FDI a country did over the period 1980—2005 and the growth in real GDP predicted by the model. This finding rests crucially on the fact that most of these countries are still in transition to FDI openness.