OBJECTIVES: To analyze what proportion of the variation in commercial prices can be explained by variables related to provider and payer characteristics in four professional services –evaluation and management office visits, medical and ancillary visits, radiology services, and surgical visits— in the state of Vermont. METHODS: We used data from the Vermont Healthcare Claims Uniform Reporting and Evaluation System (VHCURES) dataset. We included primary care claims for commercial claims, excluding Medicare and Medicaid with service dates between January 1, 2012 and December 31, 2012 (Number of claims used in the analytic sample = 1,065,434). We included the top 5 CPTs for each specialty (20 in total). Commercial price is the sum of any prepaid amounts related to the service, the amount due from a patient through copayment, co-insurance and deductible. We estimated OLS models controlling for payer-related factors (payer, health plan product, imputed payment method, patient share of payment, calendar quarter) and provider-related factors (provider size, provider region, provider type, site of service, service code modifier).  RESULTS: The results of the regression analysis show that these 10 payer and provider related factors explain approximately 57% of the price variation for evaluation and management office visits, 56% for medical and ancillary visits, 91% for radiology services, and 43% in surgical visits. The health plan product (e.g. HMO, PPO or Indemnity) explained the most price variation for evaluation and management office visits (27%); the site of service for the medical and ancillary visits (17%); service code modifier for the radiology services (73%). The unexplained variation is comparably higher in surgical services yet provider type and the provider size are by far the most important indicators for variation in price in this specialty. CONCLUSIONS: Understanding the determinants of price variation in professional services is a necessary step in the development of pricing policies for the policy makers.