Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Applying the difference-in-differences method, we show that high-speed rail (HSR) construction improves investment efficiency in China. The effect is more pronounced for companies with low information transparency and low media coverage, suggesting that HSR can mitigate information asymmetry while reducing external regulatory costs. Our analysis also shows that the effect is more powerful for non-state-owned enterprises, high-growth firms, and those companies located in core cities. Overall, our findings suggest that HSR can improve investment efficiency by shortening the travel time between firms and their investors.