A range of policy recommendations mandating gender board quotas is based on the idea that "women help women". We analyze potential gender diversity spillovers from supervisory to top managerial positions over three decades in Europe. Contrary to previous studies which worked with stock listed firms or were region locked, we use a large data base of circa 2 000 000 firms. We find evidence that women do not help women in corporate Europe, unless the firm is stock listed. Only within public firms, going from no woman to at least one woman on supervisory position is associated with a 10-15% higher probability of appointing at least one woman to the executive position. This pattern aligns with signaling, stakeholder and institutional theories, suggesting that external visibility influences corporate gender diversity practices. The study implies that diversity policies, while impactfull in public firms, might have limited effectiveness in promoting gender diversity in corporate Europe.
