RT Monograph SR 00 A1 Cremer, Helmuth A1 Lozachmeur, Jean-Marie T1 Coinsurance vs. copayments : reimbursement rules for a monopolistic medical product with competitive health insurers YR 2021 FD 2021-05 VO 21-1223 SP 17 K1 Ex post moral hazard K1 health insurance competition K1 copayments K1 imper- K1 fect competition AB This paper studies a market for a medical product in which there is perfect competition among health insurers, while the good is sold by a monopolist. Individuals diĀ¤er in their severity of illness and there is ex post moral hazard. We consider two regimes : one in which insurers use coinsurance rates (ad valorem reimbursements) and one in which insurers use copayments (specic reimbursements). We show that the induced equilibrium with copayments involves a lower producer price and a higher level of wel- fare for consumers. This results provides strong support for a reference price based reimbursement policy. T2 TSE Working Paper PB TSE Working Paper PP Toulouse, France AV Published LK https://publications.ut-capitole.fr/id/eprint/43614/ UL http://tse-fr.eu/pub/125695