Online-marketplace giant eBay has bought Decide.com, the privately held shopping research service, for an undisclosed amount.

EBay, based in San Jose, Calif., plans to use Decide’s engineers to help its 25 million sellers figure out the best way to price their products.

“We saw an incredible opportunity for them to help us and our sellers,” said Ken Moss, vice president of technology and sciences for eBay Marketplaces and the general manager of the company’s Bellevue office.

Decide’s business helps shoppers by creating predictive technology to understand price fluctuations to determine the best time to buy such items as televisions, refrigerators and circular saws online. With the acquisition, the Decide.com website will be shut down Sept. 30.

All of Decide’s 26 employees will move from its Queen Anne headquarters to eBay’s Bellevue office, except for co-founder Oren Etzioni, who took a job earlier this week as the executive director of the Allen Institute for Artificial Intelligence.

Decide Chief Executive Mike Fridgen said his team sees enormous opportunity to tap into the trove of data that eBay has generated to come up with new services.

“They are geeked out,” Fridgen said. “They cannot wait to get going on this.”

Decide raised $17 million from three Seattle venture capital firms, Vulcan Capital, the investment arm of Microsoft co-founder Paul Allen’s Vulcan; Maveron, the venture-capital firm co-founded by Starbucks CEO Howard Schultz; and Madrona Venture Group. The amount includes $8 million the company raised just last March.

Decide’s engineers will shift their focus from helping buyers get the best deals to mining eBay’s transaction history to help sellers determine the optimal price and type of sale — an auction or a “Buy It Now” sale — to move their products. Moss said making pricing more efficient ultimately helps buyers as well.

And eBay Chief Technology Officer Mark Carges said Decide engineers might also work on technology to help buyers one day as well.

“I bet they are going to find five other things to do,” Carges said.

The acquisition comes as eBay expands its Seattle-area operations, one of several Silicon Valley tech giants including Google, Facebook and Twitter that have built outposts in the region. EBay has more than 200 employees in Bellevue and has room for as many as 350 workers at its One Bellevue Center office

Many of those employees work on data mining and analysis operations. The office also works on shipping technology, another data challenge to determine the most efficient way to move products to buyers.

Jay Greene: 206-464-2231 or jgreene@seattletimes.com. Twitter: iamjaygreene