I study the welfare implications of size-dependent firm regulation policies (SDPs) in the presence of entrepreneurial risks. Although SDP has been considered a source of misallocation, I show that, once entrepreneurial risks are taken into account, SDP can improve efficiency. Quantitatively, I show that, based on French data, removing the SDP leads to output and welfare loss by 1.5% and 1.3%, respectively, in opposition to the output gain reported by the previous literature that abstracts from risks. Qualitatively, I solve an optimal non-linear SDP problem and show that the observed SDP shares certain features with the optimal SDP. The analysis uncovers a novel tradeoff between the inefficiencies of the intensive and extensive margins. In e...