Abstract: | We examine the relation between Chief Executive Officer (CEO) overconfidence and significant increases in research and development (R&D) expenditures. Although prior studies reveal a significantly positive market reaction to increases in R&D expenditures in both the long and short run, we find that long‐run stock performance is positive only for firms whose CEOs are not overconfident. Our findings, which may be attributable to overinvestment and the overestimation of future cash flows, imply that R&D resulting from overconfident behavior does not provide any value to firms. |