Predicted TFP gains under Hsieh and Klenow (2009)’s framework are sensitive to demand elasticities and returns to scale, but simultaneously estimating them is difficult. We solve this problem by developing a framework allowing for an arbitrary distribution of firm-level markups and use microdata to estimate industry-specific production elasticities, within-industry type-specific demand elasticities when types are not observed, and firm-specific distortions. We apply our model to 2005 Chinese firm-level data and find that the predicted Total Factor Productivity (TFP) gains are 44% which is half of the previous findings. While the variation in markups does not affect predicted TFP gains, it lowers the predicted increase in labor income share by one-third, suggesting lower gains to average workers due to heterogeneous markups.