We examine whether regulatory information acquisition through randomized pre-IPO on-site inspections improve broader IPO market oversight. Despite their limited scale, inspections generate significant spillover effects on concurrent, non-inspected IPOs advised by the same underwriter. These IPOs exhibit lower earnings management, fewer misstatements, more informative prospectuses, lower underpricing, reduced volatility, better liquidity, and superior long-run returns. Mechanism analyses support both regulatory learning and deterrence channels. Spillover effects are stronger for same-industry IPOs, firms with greater information asymmetry, and underwriters without political connections. Overall, direct information acquisition enhances regulators’ supervisory capacity beyond targeted inspections and improves broader IPO market oversight and outcomes.