Massachusetts's highest court told the state insurance commissioner to show his math after he cut workers' comp rates 14.6% without explaining how.
That is the kind of ruling every carrier in the state will want to read twice. In a decision released July 6, 2026, the Supreme Judicial Court of Massachusetts sided partly with the Workers' Compensation Rating and Inspection Bureau of Massachusetts (WCRIB), the body that sets the numbers every workers' comp insurer in the state has to live with. WCRIB is the only licensed rating organization for the line, and every carrier writing that coverage is a member - so when the court weighs in on how its rates get set, the whole market is affected.
Two filings were at the center of it. In December 2023, WCRIB asked to cut average rates by 7.6%, effective July 1, 2024. The commissioner said no - and ordered a far bigger cut of 14.6%. In November 2024, WCRIB asked for a 7.1% increase, effective July 1, 2025. The commissioner said no again and kept the reduced rate in place.
Most of the fight was about data. WCRIB used the two most recent years, 2021 and 2022, to estimate its "indemnity paid losses" - the money paid out on claims over time - as it had for more than twenty years. The commissioner wanted five years, 2018 through 2022, to smooth out the swings COVID-19 caused. Losses were low in 2020 and high in 2021 and 2022, and he said five years captured both. The court agreed he explained himself and the evidence backed him up.
The 14.6% figure was another matter. The court found the commissioner never explained how he landed on it. Rejecting a proposed rate and choosing a specific new one are two separate jobs, and the second one needs a reason. "As our high school mathematics teachers reminded us: you need to show your work," the court wrote. "That is true for the commissioner's calculations as well."
The court also faulted his handling of class code 9033, which mostly covers public housing authority employees. He ordered WCRIB to change the data behind those rates without adequately explaining the switch.
So the court affirmed the finding that existing rates were excessive but sent the case back. The commissioner now has to justify the 14.6% figure and explain his approach to class code 9033 for both the 2024 and 2025 decisions.
The takeaway for carriers writing workers' comp in the state: the commissioner kept his power to reject a filing and order a specific cut, but he cannot simply name a number. The math has to be on the page.
