THE HEADS OF NINE BUSINESS AND INSURANCE GROUPS sent a letter to top Beacon Hill leaders on Tuesday raising concerns about some of the proposals being considered to forestall a ballot question that would regulate hospital prices.

The letter to Gov. Charlie Baker, Senate President Stanley Rosenberg, and House Speaker Robert DeLeo indicated some of the alternatives being considered would impose new assessments on employers, health plans, or the financial reserves of health plans to provide funds that would be passed on to lower-priced health care providers in the form of one-time grants.

“This will do nothing to address the wide variation in rates among providers and will translate into higher health care costs for Massachusetts consumers and employers,” the letter said.

Service Employees International Union Local 1199 is pushing the ballot question to address pricing disparities between hospitals. Under the union proposal, licensed commercial health insurers would be barred from paying any hospital more than 20 percent above or 10 percent below the “carrier-specific average relative price” for a service. A big loser under the proposal is Partners HealthCare and its two flagship hospitals, Massachusetts General and Brigham and Women’s, which stand to lose an estimated $450 million a year.

SEIU and hospital executives have been holding private discussions to see if a ballot fight that would be costly to both sides can be avoided. The letter suggests those talks are intensifying.

The letter was signed by representatives of Blue Cross Blue Shield of Massachusetts, the Massachusetts Association of Health Plans, the Massachusetts Association of Health Underwriters, Associated Industries of Massachusetts, the Retailers Association of Massachusetts, the National Federation of Independent Business, the Small Business Service Bureau, the Mosaic Insurance Exchange, and Health Services Administrators.