Scholars and policymakers claim that Business Incubators (BIs) add value by facilitating internal cooperation between tenant firms. Taking a tenant perspective, this research investigates the impact of a tenant's length of BI tenure on the use of formal internal networking services the BI management provides, and then on the tenant's level of intra‐BI cooperation. The premise is that BI tenants use and benefit more from formal internal networking services when their socialization through participation in BI informal networking activities is low. When socialization is high they will enjoy a stronger direct effect of tenant tenure on cooperation with other tenants. Findings from data collected from a Dutch BI confirm the premise of our moderated‐mediation model. Results also show that both mechanisms complement each other and that each contributes significantly to tenants' sales growth. It lends support to the effectiveness of BI formal internal networking services, but also stresses the importance of socialization through informal networking activities.