HMA Inc., a Honolulu-based third-party administrator of self-insured health plans, has merged with a multibillion-dollar network provider in New York.

HMA combined business operations with MultiPlan Inc., which processes more than 100 million medical claims annually and is owned by large private equity funds BC Partners and Silver Lake.

The merger, completed on April 29, means more financial resources and technical expertise and a larger network of mainland providers for the small local firm, according to Harris Nakamoto, HMA’s vice president and general manager.

HMA, which began doing business in Hawaii in 2002, was formerly a subsidiary of IMX Cos., based in Tempe, Ariz. Its subsidiary, Health Management Network, is comprised of nearly 5,000 Hawaii health care providers. HMA has 70 local employees, all of whom will be retained, Nakamoto said.

He didn’t disclose financial terms of the merger.

"It gives us broader and stronger resources … but at the same time our Hawaii business remains all intact and unchanged to service the local community," he said.

HMA has six clients with more than 80,000 members. They include the AFL Hotel & Restaurant Workers Health & Welfare Trust Fund, Hawaii Teamsters Health & Welfare Trust, UFCW Hawaii Food Employers Health & Welfare Trust Fund, ILWU Local 142 Health & Welfare Trust, Hawaii Employer-Union Health Benefits Trust Fund and Times Supermarkets.

MultiPlan’s core business is national provider networks. It has more than 900,000 health care providers in its network, Nakamoto said.

Pam Walker, a spokeswoman for MultiPlan, didn’t return calls for comment as of yesterday’s deadline.

Unions and trust funds choose self-funded health plans so they can control medical benefits as well as costs.

"The key to self-funding is managing health care costs," Nakamoto said. "If they manage it well, then all the cost savings is to benefit primarily the membership."

Employers contribute money for workers’ health and welfare costs into trust funds controlled by a board of directors, typically comprised of union representatives and employers.

HMA provides back-office operations for the self-funded plans, including claims processing, customer service and network providers as well as wellness and disease management. The company does not sell insurance.