What does a relative price of investment wedge reveal about the role of investment-specific technology?

Abstract In order to identify investment-specific technology (IST), most DSGE models assume a perfect inverse relationship between IST and the relative price of investment (RPI). This paper explores this relationship and provides evidence that the RPI also responds to changes in market power, which I find constitutes a third of volatility in the RPI. To corroborate this conclusion, two competing models are produced; the first is a two-sector model with a wedge separating the identification of IST with the inverse of the RPI. The RPI wedge is then estimated using Bayesian estimation techniques. A second, richer two-sector model is produced, where firms can vary markups depending on the number of competitors. This paper finds that changes in relative markups are highly correlated with the RPI wedge and help explain the sudden increase in the RPI following the Great Recession in the United States. In addition, with endogenous price markups, non-IST shocks can explain over a third of the volatility observed in the RPI, with marginal efficiency of investment contributing approximately 30 percent of the volatility in the RPI.