International Evidence on Investment and Fundamentals, European Economic Review
If a firm's costs of installing capital are not quadratic, then its optimal investment is not a linear function of fundamentals, such as the returns and costs of capital. This study specifies a model in which a firm may face fixed, linear, and convex costs of investing, and estimates the resulting investment function using firm-level data from 11 countries. The evidence suggests important nonlinearities, consistent with the presence of fixed or other non-quadratic costs, in the relationship between investment and fundamentals for most countries. These findings are statistically signficant at the level of the firm, and economically significant when aggregated by country.
Eberly, C. Janice. 1997. International Evidence on Investment and Fundamentals. European Economic Review. 75(2): 1055-1078.