Enrollment in Health Insurance

Enrollment Trends
(August 2019 Report)

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 6.5 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.

The August 2019 edition, which covers the period between March 2017 and March 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.


Enrollment Trends Findings (August 2019)

  • Private commercial insurance enrollment remained stable overall, covering approximately 4.1 million Massachusetts residents. Over 90% of Massachusetts residents who enroll in private commercial insurance do so through their employer, although a growing proportion are individual purchasers.


  • Between March 2017 and March 2019, the merged market grew by 0.8% (+6,000 members). 1


  • The number of Massachusetts residents receiving primary, medical insurance coverage from Medicare continued to grow to 1.1 million by March 2019. This growth was concentrated within Medicare Advantage plans (+11.8% from March 2017), where Tufts remained the largest payer.


  • In March 2019, 1.2 million Massachusetts residents relied on MassHealth for their primary, medical coverage, a decline of -9.4% compared to March 2017. Another 581,000 residents received partial or secondary coverage from MassHealth, an increase of 1.4% over the two-year 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.

Enrollment Trends - March 2017 through March 2019

If you are unfamiliar with using a Tableau interface, please watch this video.

Updated August 2019

Previous Enrollment Publication Materials

2019 Publications

February 2019


2018 Publications

August 2018


February 2018


2017 Publications

August 2017


March 2017


2016 Publications

July 2016


February 2016