Coldwell Banker Purchases Bay Area Brokerage : Acquisitions: It becomes the largest residential real estate company in that region with Fox & Carskadon deal.

In its largest acquisition in four years, Coldwell Banker Corp. said Thursday that it has agreed to buy a Northern California brokerage, which would make it the largest residential real estate company in the San Francisco Bay area.

Coldwell Banker said it will acquire the Fox & Carskadon chain of 31 offices and more than 1,100 agents, which it will combine with its own office network and sales force in the Bay Area. Terms were not disclosed.

“It’s a very big one for us,” said Bob Arrigoni, president of Coldwell Banker Residential Brokerage. “This fits so well in our existing niche market. It’s a perfect fit.”

He said that Coldwell Banker is strong in San Francisco, Marin County and the East Bay area, while Fox & Carskadon is predominant in the cities of San Mateo and Santa Clara.

The new entity will be called Coldwell Banker Fox & Carskadon. Arrigoni said that all of Fox & Carskadon’s current employees will be kept, although some offices may be combined.

Coldwell Banker Residential Brokerage has 317 company-owned offices and another 1,829 franchisees. Its largest previous acquisition was 99-office Schlott Realtors of Wayne, N.J., in 1991.

The Schlott deal made Coldwell Banker the nation’s third-largest residential real estate brokerage after Century 21 and ReMax. A Century 21 spokesman in the Bay Area said that its position in the San Francisco market will not be threatened by the Coldwell-Fox & Carskadon merger.

Industry observers said they think Coldwell Banker is making a good move and that the acquisition reflects continuing good fortune at the real estate concern.

“It gives them tremendous new regional opportunity,” said Steve Murray, co-editor of the newsletter Real Trends, based in Highlands Ranch, Colo. “They are in an expansion mode. It is indicative of their management group,” he said, which is “very aggressive and very well respected.”

John Featherston, publisher of National Relocation and Real Estate Magazine in South Norwalk, Conn., said Coldwell Banker is making a significant move that “gives them new market share.”

By having offices across the Bay Area, Coldwell Banker will be able to market itself more effectively, Featherston said. Also, he said, it can continue to concentrate on home resales in major population areas, which typically have faster turnover than smaller cities or towns.