Intervention by the state's attorney general in the rate-making process has led to 12.9% drop in workers' compensation premiums, the office announced Thursday.

AG Maura Healey

The rollback will save Massachusetts businesses about $150 million, Attorney General Maura Healey said in a news release.

“When we lower the rates for workers’ compensation insurance, we protect workers and allow businesses to invest in higher wages and growth," she said.

The Workers' Compensation Insurance Rating Bureau of Massachusetts filed a proposal last December to lower rates by 11%. But after a public hearing and review of workers' compensation data, the Attorney General's Office argued that rates could go even lower, the office said.

The 12.9% reduction is the result of a final agreement with the State Rating Bureau and the Workers' Compensation Rating and Inspection Bureau.