This study examines the impact of major health insurance reform on payments made in the health care sector. We study the prices of services paid to physicians in the privately insured market during the Massachusetts health care reform.  The reform increased the number of insured individuals as well as introduced an online marketplace where insurers compete.  We estimate that, over the reform period, physician payments increased at least 10.8 percentage points relative to control areas. Payment increases began around the time legislation passed the House and Senate---the period in which their was a high probability of the bill eventually becoming law. This result is consistent with fixed-duration payment contracts being negotiated in anticipation of future demand and competition.