1. The reported t-statistics are based on robust standard errors adjusted for clustering at the firm level. ***, **, and * denote statistical significance at the 1%, 5%, and 10% levels, respectively. that each industry-year contain at least four firms. The sample period is 1996-2012. The reported t-statistics are based on robust standard errors adjusted for clustering at the firm level. ***, **, and * denote statistical significance at the 1%, 5%, and 10% levels;1% and 99% levels to mitigate the influence of outliers. In Models 1 and 2, we proxy for the degree of product specialization using R&D expenditures. A firm is classified as a high-(low-) R&D intensity firm in a given year if its R&D-to-sales ratio is greater (smaller) than 0.1% two years before the base year,1994