Objective To understand patient loyalty to providers over time, informing effective population health management. Study Setting Patient care‐seeking patterns over a 6‐year timeframe in Minnesota, where care systems have a significant portion of their revenue generated by shared‐saving contracts with public and private payers. Study Design Weibull duration and probit models were used to examine patterns of patient attribution to a care system and the continuity of patient affiliation with a care system. Clustering of errors within family unit was used to account for within‐family correlation in unobserved characteristics that affect patient loyalty. Data Collection The payer provided data from health plan administrative files, matched to U.S. Census‐based characteristics of the patient's neighborhood. Patients were retrospectively attributed to health care systems based on patterns of primary care. Principal Findings I find significant patient loyalty, with past loyalty a very strong predictor of future relationship. Relationships were shorter when the patient's health status was complex and when the patient's care system was smaller. Conclusions Population health management can be beneficial to the care system making this investment, particularly for patients exhibiting prior continuity in care system choice. The results suggest that co‐located primary and specialty services are important in maintaining primary care loyalty.