The relation between the volatility of R&D expenditure and stock return may be influenced by disruptive adjustment costs, emerge from earnings management, or reflect the actions of managers attempting to control the overinvestment of technocrats. Using 5,178 publicly listed US firms from 1980 to 2018, we find a negative relation between R&D volatility and return, which is moderated by firm size. We conclude that investors react negatively to the disruptive effect of changes to R&D expenditure, except for small firms. In small firms, the benefit of the governance mechanism of varying R&D expenditure to control overinvestment outweighs the cost of disruption.

研发支出的波动性与股票收益之间的关系可能受到破坏性调整成本的影响，可能来自盈余管理，也可能反映出管理人员试图控制技术专家过度投资的行为。使用1980年至2018年间的5,178家美国上市公司，我们发现R＆D波动率与回报之间存在负相关关系，这种关系由公司规模来缓和。我们得出的结论是，除小公司外，投资者对研发支出变化的破坏性影响产生负面反应。在小公司中，改变研发支出以控制过度投资的治理机制所带来的收益大于破坏的代价。