2018 Rate Hikes: Massachusetts: ~6.9% rate hikes if CSR payments made, ~24.4% if they aren't
Massachusetts has one of the stablest statewide insurance markets, no doubt in large part due to their having instituted the precursor to the ACA, "RomneyCare", 4 years earlier. Massachusetts also merged their small business and individual market risk pools, which helps stabilize things. As a result, they have a high number of carriers participating in their ACA exchange and are among the few states with single-digit average rate hikes...assuming CSR payments are forthcoming and the individual mandate is properly enforced.
Assuming CSR payments aren't made, I used the Kaiser Family Foundation's 19% average estimate for Silver plan hikes due to the CSR factor. Since a whopping 92% of MA's exchange enrollees chose Silver plans (it looks like MA's unique "ConnectorCare" plans are considered Silver as well), that means an average CSR factor of around 17.5 points across the entire individual market.
Most of the carrier rate filings included their current membership numbers, but three didn't: BCBSMA, HPHC and Tufts Health. For these, I relied on the July MA Health Connector report, which shows Tufts Health Direct eating up a whopping 50% of ConnectoCare enrollees and 37% of other exchange policy enrollment, for a total of over 117,000 enrollees.
With those caveats in mind, as far as I can tell, MA is looking at around a 6.9% average rate increase if CSR payments are made...but assuming Kaiser's estimates are accurate, 24.4% if they aren't.