This paper presents the first empirical evidence showing that the marriage of a member of the controlling family adds value to public corporations. The results, based on a uniquely comprehensive data set from Thailand, show that the family firm’s stock price increases when the partner is from either a prominent business or a political family. Abnormal returns tend to be higher for firms whose operation depends on extensive networks. In contrast, marriages to ordinary citizens are not associated with any abnormal returns. These findings are generally supportive of the value of networks in general and marriage in particular.

We find inherited family firms more important in postwar Japan than generally realized, and also performing well on average. Non-consanguineous heir-run firms outperform blood heirs' firms, and roughly match founder-run listed firms, while blood heirs surpass professional managers at running family firms. Further, succession events suggest that adopted heirs “cause” elevated performance. We suggest that heir-run firms do well because non-consanguineous heirs displace the least talented blood heirs, the non-consanguineous heir “job” motivates professional managers, and the threat of displacement encourages blood heirs' effort and human capital accumulation, mitigating the “Carnegie conjecture” that inherited wealth deadens talent.