Coldwell Banker Pacific Properties has bought a big piece of a rival in a move that makes Hawaii’s largest residential real estate brokerage firm considerably bigger.

The firm announced Friday that it acquired the Oahu operations of Century 21 All Islands Fine Homes & Estates, which includes four offices and about 150 agents.

A purchase price was not disclosed.

The acquisition represents a 27 percent expansion for Coldwell Pacific, which had about 550 agents before adding the team from All Islands and now has about 700 agents.

Coldwell Pacific, which had five residential brokerage offices, also gains three new offices in Hawaii Kai, Waikele and Waikiki from All Islands and will keep them open. All Islands recently closed a Kailua office, and a corporate headquarters on Makaloa Street in Honolulu will close.

As part of the acquisition, the co-owners of All Islands, Jim Wright and Cheryl Dillon, will become sales agents for Coldwell Pacific.

The All Islands company is one of several Century 21 franchises in Hawaii. Wright said All Islands or its predecessors had been the top producer among Hawaii Century 21 franchises for several decades.

Two All Islands offices on Hawaii island were not included in the sale to Coldwell Pacific, but were sold to rival Hawaii island firm Windermere C and H Properties.

Wright, 67, said he and Dillon, his business and life partner, started their first real estate firm, Century 21 Hale Ohana, in 1993 with other partners and then acquired 18 other firms that were folded into what became All Islands. He said he and Dillon will form a sales team and will keep active in the industry but also plan to vacation more.

Mike James, president of Coldwell Pacific, said All Islands presented a good fit in terms of office locations and corporate culture. “It was like a perfect marriage,” he said. “It is a big deal for us. We’re very excited about it.”

Coldwell Banker and Century 21 are franchise brands owned by the same company, New Jersey-based Realogy Holdings Corp., which also owns other real estate franchise brands, including Better Homes and Gardens Real Estate, ERA and Sotheby’s International Realty.

Like All Islands, many brokerage firms under Realogy brands are independently owned and operated, and sales agents are independent contractors.