We investigate potential mechanisms through which market-wide sentiment affects firms’ innovation activities. We provide evidence for the financing channel by showing that financially constrained firms are more likely to issue equity and invest more in research and development (R&D) than financially unconstrained firms at high market sentiment. Using time-varying manager sentiment measures, we find suggestive evidence for a sentiment spillover channel whereby market sentiment affects R&D investments through influencing manager sentiment. Furthermore, better patent portfolios are produced from R&D investments stimulated by high market sentiment. Market sentiment has a stronger impact on R&D than the capital expenditures of financially constrained firms.

We use the 2015 Chinese stock market crash to study the effects of government stock purchases. The Chinese government purchased stocks to stabilize the markets through state-owned financial institutions known as the “National Team.” We find that the intervention led to reduced volatility and price informativeness. These impacts are driven by the disclosure of government portfolios. Consistent with investors having a stronger incentive to acquire government intervention information instead of fundamental news, we find reduced information production and information asymmetry following intervention disclosure. The article suggests that government stock purchases involve a trade-off between stability and informational efficiency.