Proponents of minority shareholder protection state that national legal institutions protecting small investors boost stock markets and, in turn, the long-term performance of countries. In this paper we empirically challenge this argument. We perform three-stage least squares estimation on a sample of 48 countries during 19932006 and find that countries with stronger shareholder protection tend to have larger market capitalisation but also lower innovative activity. We cope with stock market endogeneity and industry heterogeneity, and circumvent omitted variables bias, so that this finding is unlikely to be driven by misspecification problems. The estimation results are interpreted, arguing that stronger shareholder protection may depress rather than encourage the most valuable corporate productions, because it enables small and diversified shareholders to play opportunistic actions against undiversified stockholders, after specific investments are undertaken by the company; innovative activity, largely based on specific investing, is particularly exposed to this problem.