Institutional embeddedness of markets and institutions exercising social control over markets have been topics of research for economic sociology for a long time. Historically, business communities created their own regulations, before using the State to legalize and enforce their norms. This article presents a specific form of social control of business, the French Commercial Court, a four and a half century-old judicial and consular institution. Complex processes of recruitment of consular and lay judges (who are voluntary business people sponsored by their trade associations) are examined at the Commercial Court of Paris. The judges are shown to coopt each other both formally and informally. The existence of several recruitment and cooptation paths appears to be one of the factors explaining the surprising longevity of this form of joint regulation of business.