In testing moral hazard and tax benefit hypotheses regarding defined benefit plan funding and contribution incentives by incorporating sponsors’ bankruptcy risk, the authors proposed that high-bankruptcy-risk sponsors have a strong moral hazard incentive because the put value of the U.S. Pension Benefit Guaranty Corporation guarantee is high. For low-bankruptcy-risk sponsors, the put value is low; maximizing tax benefits associated with pension contributions becomes a powerful incentive. Results based on sponsors’ voluntary contributions support both hypotheses.