Young and technology-oriented firms suffer from asymmetric information in seeking access to finance. An increase in stock liquidity can improve a firm's stock price informativeness and mitigate such information problems. We expect that firms will patent less when they face an increase in liquidity if patenting is used as a costly signal mechanism to demonstrate firm quality. By examining an exogenous policy shock that dramatically improves the stock liquidity of treated firms in China's National Equities Exchange and Quotations (NEEQ) market, we document evidence that treated firms patent less after the shock. Our findings reveal the importance of liquidity in reducing the deadweight costs caused by asymmetric information and the signaling value of patenting, and urge caution regarding the sole use of patent applications to measure innovation performance in entrepreneurial firms.