In Switzerland a legal prohibition of volume-based bonus agreements has been initiated which is expected to take force at the beginning of 2021. Bonus agreements for physicians pose a risk to unbiased indication, possibly leading to over-, under- and misuse of medical care. In order to investigate physicians' perceptions of bonus agreements and reflect on them from an ethical point of view, we conducted a qualitative interview study with Swiss senior physicians. The remuneration system is complex and diverse so that the interviewed physicians were not always able to explain in detail to which targets the variable components of their salary were linked. Study participants were aware of their ethical responsibility regarding non-biased indication and cost-effective medicine. All rejected volume-based bonus agreements. Target agreements should generally have a clear, comprehensible function and always contain a component related to the quality of care delivered. Critical attention should go beyond a narrow focus on volume-based bonus agreements to include other volume-oriented target agreements and reimbursement systems that have the potential to negatively affect patient care.