Enrollment in Health Insurance

enrollment summaries




Monthly Enrollment Summaries
(Through May 2020)

To provide more rapid insight into the impact of COVID-19 on insurance coverage in the Commonwealth, CHIA is now producing monthly enrollment data summaries by key market sectors. This new report series is in addition to CHIA’s regular biannual Enrollment Trends reports.

This month’s publication includes enrollment figures through May 2020. CHIA intends to continue reporting on Massachusetts insurance coverage on a monthly basis as the impact of COVID-19 is further felt across insurance categories and market sectors.

Enrollment Trends
(through September 2019)

Enrollment Trends
(Through September 2019)

Additionally, twice a year, CHIA updates its analysis of Massachusetts health insurance enrollment trends for the most recent trailing two-year period to give researchers and policymakers insight into the market. Approximately 6.4 million Massachusetts residents have health insurance coverage, where coverage is defined by unique Massachusetts residents with primary, medical membership in the 14 largest commercial payers, MassHealth (Medicaid), or Medicare.

This edition, which covers the period between September 2017 and September 2019, includes an interactive dashboard, a detailed databook, and technical appendix.

Enrollment measures are also reported in CHIA's Annual Report on the Performance of the Massachusetts Health Care System.

  • From September 2017 and September 2019, private commercial insurance enrollment decreased slightly (-1.4%), covering approximately 4.0 million Massachusetts residents.


  • Between September 2017 and September 2019, the merged market grew by 0.7% (+5,000 members).1


  • The number of Massachusetts residents receiving primary, medical insurance coverage from Medicare continued to grow to over 1.1 million by September 2019. 


  • In September 2019, nearly 1.2 million Massachusetts residents relied on MassHealth for their primary medical coverage, a decline of -4.5% compared to September 2017.
    Another 592,000 residents received partial or secondary coverage from MassHealth, an increase of 4.1% over the same period.


1. The Massachusetts merged market includes private commercial insurance sold to individuals or small groups (50 or fewer eligible employees) under fully-insured plans.

Updated March 2020

Previous Enrollment Publication Materials

2020 Publications

March 2020


2019 Publications

August 2019


February 2019


2018 Publications

August 2018


February 2018


2017 Publications

August 2017


March 2017


2016 Publications

July 2016


February 2016