In 2005 and 2006, the split-share structure reform converted the nontradable shares of most domestic public firms in China to tradable shares. This conversion imparted a drastic supply shock to the public market. Studying this unique event, we provide direct evidence to support an inelastic demand curve for stocks. Abnormal returns of the sample firms resulting from the reform are found to be negatively associated with the size of the supply shock. This finding is free from the confounding information effects present in many prior studies of stock price elasticity. It is also robust after controlling for opposite price impacts of ROA, firm size, and ownership concentration.