In recent years, US investment has been lackluster, despite rising valuations. Key explanations include growing rents and growing intangibles. We propose and estimate a framework to quantify their roles. The gap between valuations -- reflected in average Q -- and investment -- reflected in...

We propose a model that starts from the premise that intangible capital needs to be stored on some medium --- software, patents, essential employees --- before it can be utilized in production. Storage implies that intangible capital may be partially non-rival within the firm, leading to scale...

Investment in intangible capital--in particular, research and development--increased dramatically since the 1990s. However, productivity growth remains sluggish in recent years. One potential reason is that a significant share of the increase in intangible investment is geared toward consumer...

The impact of an economic shock depends both on its severity and the resilience of the economic response. Resilience can include the ability to relocate factors, for example, even when new technologies or skills are not yet at the ready. This resilience per se buffers production and has an...

We document that the rise of factors such as software, intellectual property, brand, and innovative business processes, collectively known as "intangible capital" can explain much of the weakness in physical capital investment since 2000. Moreover, intangibles have distinct economic features...

Which investment model best fits firm-level data? To answer this question we estimate alternative models using Compustat data. Surprisingly, the two best-performing specifications are based on Hayashi's (1982) model. This model's foremost implication, that Q is a sufficient statistic for...

When factors of production can be adjusted costlessly, the mix of factors can be considered separately from their scale. We examine factor choice and utilization when investment is irreversible and subject to a fixed cost, so that the capital stock is a quasi-fixed factor that is adjusted...

When investment decisions cannot be reversed and returns to capital are uncertain, the firm faces a higher user cost of capital than if it could reverse its decisions. This higher user cost tends to reduce the firm's capital stock. Opposing this effect is the irreversibility constraint itself:...

Capital investment decisions must recognize the limitations on the firm's ability later to sell off or expand capacity. This paper shows how opportunities for future expansion or contraction can be valued as options, how this valuation relates to the q-theory of investment, and how these options...

Investment is characterized by costly reversibility when a firm can purchase capital at a given price and sell capital at a lower price. We derive an explicit analytic solution for optimal investment by a firm facing costly reversibility. In addition, we derive a local approximation to the...