The buyer, Blum Capital Partners LP, launched a $15.50-a-share offer for CB Richard Ellis in November. A special board that CB Richard Ellis formed to weigh the offer and explore other opportunities accepted a sweetened, $16-a-share proposal over the past weekend, officials at the two companies say.

"We appreciate the confidence of the board in accepting our offer as the best alternative for the company, its shareholders and employees," Blum Capital chairman Richard C. Blum says in a statement. "We are pleased to partner with management to guide the company in its next stage of growth."

By most measures, LA-based CB Richard Ellis is the nation's largest commercial broker. It has about 250 offices worldwide and roughly 10,000 employees. It also manages about 600 million sf worldwide, including 422 million in the US.

Blum Capital Partners already owns about 38% of the company's stock. The investment group includes a number of current CB Richard Ellis executives and directors, among them CEO Ray Wirta and Brett White, the company's chairman of the Americas.

The group also includes the Freeman Spogli & Co. investment firm and Newport Beach based-Koll Holding Co., which is run by Orange County real estate mogul Donald Koll, another CB Richard Ellis director.

CB Richard Ellis' brokers and other employees will be offered the opportunity to invest in the newly formed company, Richard Blum says. No jobs are expected to be lost, he adds.

The buyer is technically Blum CB Corp., an entity that Blum Capital formed to complete the merger. Blum CB hopes to close the deal by the end of the second quarter.

Much of the purchase would be financed with debt. Blum CB says it has received commitment letters from Credit Suisse First Boston and DLJ Investment Funding Inc. for $400 million of senior debt and $75 million of mezzanine debt. CSFB has also committed to providing a $100-million working capital line.

The deal must still be approved by holders of the 62% of CB Richard Ellis stock that Blum Capital doesn't already own.