Weichert Realtors operates 17 affiliate offices in the Bay State, including Weichert Realtors Hunter Properties in Plainville.

Kim Cook started her Billerica real estate firm three years ago just as the housing market started its downward spiral.

Soon after launching her company, she was getting offers from franchises and competitors. Cook resisted them, preferring to remain independent. But she soon realized that even though her business was doing OK, she wanted to do even better. She affiliated with New Jersey-based Weichert Realtors last month.

“We did well with the market the way it is but with most sellers wanting one-stop shopping and relocation, we just needed a boost in business,” said Cook, owner of Weichert Realtors Cook and Co.

“I was starting to think, ‘I have to do something; I want to do something.’ I wanted to give the agents more of an opportunity and I wanted to be able to offer more services to the buyers and sellers in one spot,” she said.

Sluggish market conditions have helped Weichert attract more firms to its network. When the company started its expansion into New England in 2004, it only had two offices in Massachusetts. Since then, Weichert has added 15 more affiliate offices, including Weichert Realtors Synergy in Wellesley Hills, which opened this month.

The company’s other Bay State offices include locations in Auburn, Boston, Cambridge, Lakeville, Lexington, Marlborough, Medfield, Newton Centre, Northborough, Norwell, Osterville, Plainville, South Easton and two in New Bedford. In all, there are 358 sales associates working in Weichert’s Massachusetts offices.

Weichert’s expansion has been impressive, according to some industry watchers.

“For a company [that] is relatively new to a marketplace and not known by the natives to come in and sign up 17 offices in a couple of years, that’s a very strong performance,” said Steve Murray, editor of Real Trends, an international publication that tracks the market.

Weichert has 335 franchised offices in 35 states. By comparison, other regional firms such as Seattle-based John L. Scott Real Estate and Pittsburgh-based Howard Hannah Real Estate Services have far fewer. John L. Scott, which has been franchising for the last 18 years, has 105 franchised offices in three states while Howard Hanna has 35 franchises in four states.

“They [Weichert] have grown much bigger and much faster than that peer group over the last four or five years,” Murray said.

‘Appetite for Growth’

William Scavone, Weichert’s senior vice president of development, said about 45 companies from Massachusetts have come to the company’s Morris Plain, N.J., headquarters since 2005 to explore joining Weichert.

“It all comes down to [whether] the companies have an appetite for growth. If they don’t really want to grow their business Â… it doesn’t make sense,” to join Weichert, he said.

Independently owned companies struggling through the sagging market are reaching out to large networks. “In this marketplace they tend to look for assistance in growing business, and what they look for is someone who has a proven system for doing that,” Murray said.

Scavone said it’s been easier to expand the franchise now than it was three years ago. “With the market turning, people are realizing that a lot of the success they had during the hot market was happening because it was just happening,” he said.

Weichert offers a system for everything from recruiting new agents, to managing leads, to running open houses, to doing listing presentations, explained Scavone.

Cambridge broker Bill Luther was so impressed that after 20 years of operating his business, Channing Real Estate, he joined Weichert last July. He said his first introduction to the company came through the relocation business that Weichert was funneling to his firm.

“As I began to suspect that the market was changing, I began to think back to the last downturn I experienced in 1989 and 1990, and began to think about how it was a struggle to move through that downturn,” said Luther. “I thought aligning myself with a national organization would give me lines of incoming business that I would never have been able to have as an independent.”