An Examination of Long-Term Abnormal Stock Returns and Operating Performance Following R&D Increases

Abstract:     
We examine a sample of 8,313 cases, between 1951 and 2001, where firms unexpectedly increase their research and development expenditures (R&D) by a significant amount. We find consistent evidence of a mis-reaction, as manifested in the significantly positive abnormal stock returns that our sample firms' shareholders experience following these increases. We also find consistent evidence that our sample firms experience significantly positive long-term abnormal operating performance following their R&D increases. Our findings suggest that R&D increases are beneficial investments, and that the market is slow to recognize the extent of this benefit (consistent with investor underreaction).

Keywords: R&D, market efficiency

JEL Classification: G14, G31

Accepted Paper Series