Mattress Firm Holding Corp. announced the completion of its acquisition of The Sleep Train, the largest West Coast-based bedding specialty retailer, for $425 million.

The combined business operates more than 2,000 mattress specialty retail stores and 70 distribution centers across 40 states, and further solidifies Mattress Firm’s standing as the nation’s largest mattress specialty retailer.

“We are ecstatic to reach this milestone in our company’s growth and couldn’t be happier about our future together,” said Steve Stagner, Mattress Firm’s CEO. “With the Sleep Train business, we become the first border to border, coast to coast multi-brand mattress specialty retailer in the United States, with pro forma sales of approximately $2 billion a year.

“We believe that our combined expertise will allow us to generate significant benefits for our stakeholders in the future. We are highly focused on integrating the two businesses and providing as seamless a transition as possible for all of our employees, customers and other stakeholders,” Stagner said.

Effective immediately, Dale Carlsen, CEO of Sleep Train, becomes president and chief strategy officer of Mattress Firm and will join its board as vice chairman. Rob Killgore, chief operating officer of Sleep Train, becomes co-chief operating officer Mattress Firm along with current COO Ken Murphy.

Ron Mittelstaedt, chairman and CEO of Waste Connections Inc., also joins the Mattress Firm board effective with the closing of the acquisition. The company will maintain a West Coast corporate headquarters near Sacramento, Calif., where Sleep Train has been based.

Said Carlsen, “This transaction is the culmination of nearly 30 years of hard work by the Sleep Train family of employees and the beginning of the next chapter in our phase of growth. I look forward to bringing our two teams together for the benefit of our customers, our employees and the communities we serve.”

The acquisition is subject to working capital and other customary adjustments, along with the assumption of certain additional liabilities totaling approximately $15 million, Mattress Firm officials said.

They said the company expects to receive future annual cash income tax benefits of approximately $11 million over the next 15 years from deductible tax basis goodwill generated from the transaction, subject to the company’s ability to generate future taxable income.

Sleep Train operates about 310 specialty mattress stores in California, Oregon, Washington, Idaho, Nevada and Hawaii, and reported net sales of approximately $471 million for the 2013 fiscal year.