SAN JOSE — Now the speculation begins: Who is the mystery tech company set to call San Jose’s biggest-ever office park home?

It didn’t take long for the rumor mill to start churning after city officials Wednesday gave final approval to a 2 million-square-foot North San Jose office project that is expected to start construction this year. Renowned developer Peery-Arrillaga says it has a company committed to lease the buildings, worth an estimated $700 million, but won’t say who. Could one of Silicon Valley’s tech titans such as Google or Apple be moving or expanding from a nearby suburb? Did an out-of-towner like Microsoft or Amazon finally come to its senses and ditch Seattle?

With space for 8,000 to 10,000 employees spread out over 10 seven-story buildings, the project near Mineta San Jose International Airport is twice the size of Facebook’s Menlo Park campus. And right at the split of Highway 101 and Interstate 880, it’s perhaps the last prime location left in the area and one that real estate brokers say is the largest Silicon Valley office project they’ve ever seen.

“This would be the proverbial grand-daddy of them all,” said Jim Beeger, a senior vice president at Colliers International in San Jose, adding, “We’re dying to find out” who’s moving there.

“That’s what we all want to know,” Beeger said.

Mayor Chuck Reed, who said he is the only person in City Hall who knows the identity of the company, confirmed it’s in the tech sector but said he would respect the developer’s wishes to announce the tenant on its own terms. It’s unclear when that will be.

“I haven’t told anybody,” Reed said Wednesday. “I’m going to keep it a secret.”

Palo Alto-based Peery-Arrillaga — co-founded by billionaires Richard Peery and John Arrillaga, who have built campuses for companies such as Apple and Hewlett-Packard — declined to comment, citing a general policy that it doesn’t talk to the press.

The tenant would easily become the second-biggest private sector employer in San Jose, behind Cisco Systems, which had more than 13,000 workers on site as of last year.

The city’s approval came unceremoniously Wednesday morning in an empty council chamber as planning department official Steve Piasecki gave his thumbs up. The entire approval process took just six months, with no City Council or even planning commission hearings, as it required no zoning changes or other major municipal approvals. It’s part of the city’s ongoing effort to “move at the speed of business” after criticisms that developments get stuck for years in City Hall bureaucracy.

Construction will begin sometime in 2014 on the largely vacant portion of the 31.1-acre site at Brokaw Road and First Street. As part of the project, the Bay 101 casino on the site will be demolished as the cardroom owners had announced plans last year to move down the street to a larger, new facility by 2017.

The campus includes about 7,000 parking spaces and all the standard modern amenities, such as a fitness center.

Reed estimates the city will get an extra $7 million in annual property tax revenues from the project plus millions of dollars in one-time construction fees.

Still, the City Council in December cut the development traffic impact fee by more than half for projects of at least 1 million square feet — a move that, for now, benefits only Peery-Arrillaga. That cost the city a one-time total of $6 million.

Altogether, similar but smaller incentives given to other companies building in North San Jose have left the city $40 million short for needed traffic upgrades in the past few years. City leaders argue they need to compete with their cheaper Silicon Valley neighbors for businesses and have also been paring back design requirements that can drive up costs for developers.

“We were trying to encourage people to move ahead quickly,” said Reed, who has been working with Peery-Arrillaga on a potential project since he was a council member early last decade. Of the vacant part of the land, he said: “Right now we’re getting nothing out of that property.”

The project would further develop the largely industrial north side of the city, which has been growing quickly. In the past few years, Cisco Systems, Samsung Semiconductor and Ellis Partners have started projects worth more than $500 million combined on the north side. The entire city has about $3 billion worth of development applications going on now and has seen the number of proposed projects increase 17 percent in the past year following similar bumps of activity in nearby cities.

“It’s really San Jose’s time in the cycle to shine,” said Kim Walesh, the city’s economic director.

Contact Mike Rosenberg at 408-920-5705. Follow him at Twitter.com/rosenbergmerc.