We propose a tax-adjusted q model with physical and intangible assets and estimate the effect of bonus depreciation in the United States in the early 2000s. We find that investment responds moderately to tax incentives; however allowing for heterogeneity reveals that intangible-intensive firms are more responsive than physical-intensive firms and their differences increase with firm size. Accounting for intangible assets increases the estimated total investment response from 3.7 to 14.3 percent among the largest 500 firms. Our results imply that understanding the behavior of large and intangible-intensive firms has important implications for the design and evaluation of investment policy. JEL: H25, G31, E01 Keywords: investment tax incentives, intangible assets, q model of investment, bonus depreciation