Abstract
A key feature of markets for repugnant transactions is that certain transactions seem to raise moral concerns only when they involve high monetary incentives. Using a framed field experiment with a representative sample, I show that these preferences exist, and I investigate why people display it. Participants can permit or prevent a third party from being financially compensated for registering as a stem cell and bone marrow donor. I find that a substantial fraction of individuals permit a low payment but prevent high monetary incentives. With the help of experimental treatment variation, I show that their preference to prevent high incentive offers is caused by the desire to protect individuals who are persuaded by high incentives. Evidence from a survey experiment with ethic committees emphasizes the practical importance of this finding.