This study contributes to the literature by providing the first empirical evidence that mobile app performance contains value-relevant information for the stock market. Our findings suggest that abnormal app downloads and abnormal daily users are positively associated with the following-month stock return, and this association is robust after controlling for other factors. There are several ways to extend the analyses reported here. First, we have not controlled for the influence of analyst recommendation and earnings forecasts yet. Second, it is possible to construct the panel dataset at different levels of granularity, such as daily or weekly, to validate the results we have obtained so far. Finally, it is also interesting to investigate how mobile app performance affects revenue surprise and earnings surprise. To conclude, our study provides important managerial implications for investors by documenting the investment value of mobile app performance data in the stock market.