. Successful implementation of an effective EU MDR-compliant PMS requires a systems approach which requires appreciation of not only the organizational context within which PMS operates but also the knowledge management as it relates to PMS generated data, information, knowledge, and wisdom. . It not only explores the interfaces between risk management and PMS but also discusses the postmarket aspects of risk surveillance and their accomplishments. Part 4 details an important upcoming topic with relevance going beyond EU MDR. Risk-based incident trending for postmarket signal detection is quickly becoming an expectation from most regulatory agencies and EU MDR is one of the first regulations to expressly document this requirement. The regulation asks for a methodology to gauge “statistically significant increases” in a certain subset of postmarket incidents. This article details salient features of any such method such that any chosen tool can act as a postmarket risk monitor and, if used right, can also convert the lagging indicator of complaints and incidents into a leading key risk indicator. Key risk indicators can help establish preemptive preventive actions before benefit-risk profile can be adversely impacted.