This study employs the launch of local government public data open platforms as a natural experiment to empirically investigate the effects of government data opening on corporate financial asset allocation. The findings reveal that government data opening significantly diminishes corporate financial asset allocation levels, with this effect being particularly pronounced in non-state-owned enterprises, early-stage firms, and organizations with limited digital transformation. Mechanism analysis indicates that government data opening influences corporate financial asset allocation by moderating management’s dual motivations: precautionary and substitution. Furthermore, the quality of publicly accessible government data is a critical factor in constraining corporate financial asset allocation. Additionally, government data opening is associated with an increase in corporate real investment levels, thereby facilitating growth in regional real investment and yielding a substantial positive impact on the real economy.