A majority interest in Soundpath Health, a Federal Way-based provider of Medicare Advantage health plans, has been acquired by the parent company of Tacoma’s Franciscan Health System.

Catholic Health Initiatives, which has its headquarters in Englewood, Colo., is paying approximately $24 million for its share of Soundpath. The Washington insurance commissioner must approve the deal before it becomes official.

Under the proposed agreement, Soundpath Health’s previous owner, Physicians of Southwest Washington and Northwest Physicians Network, would transfer majority interest to an affiliate of Catholic Health Initiatives (CHI). The affiliate would manage Soundpath.

CHI owns Franciscan Health System, which operates five hospitals in Pierce and King counties – St. Joseph Medical Center in Tacoma, St. Anthony Hospital in Gig Harbor, St. Clare Hospital in Lakewood, St. Francis Hospital in Federal Way and St. Elizabeth Hospital in Enumclaw. Nationally, the non-profit CHI has 76, a combined 40 long-term care, assisted-living and residential facilities, two nursing colleges and other health services in 19 states.

CHI’s annual revenue of more than $10.5 billion makes it the second-largest Catholic-run healthcare system in the U.S., according to CHI.

“Knowing that greater collaboration is the future of healthcare, we evaluated many different options” before choosing CSI as “the right partner to serve and support people with Medicare,” said Mariella Cummings, chief executive officer of Physicians of Southwest Washington and chairwoman of Soundpath’s board of directors.

Soundpath officials said its services will be bolstered by the increased “capitalization” of the CHI deal.

“This partnership will afford investment in new systems and resources and offer opportunities for continued expansion,” said Christine Tomcala, CEO of Soundpath Health.

Soundpath was founded in 2007 as a physician-owned health plan for Medicare beneficiaries. It has more than 6,500 providers for its approximately 17,000 plan subscribers in nine counties in Washington.