SUNNYVALE — Meta, the tech titan whose apps include the Facebook social network, has completed a huge lease in Sunnyvale in a deal that marks a big expansion for the company.

In the largest private-sector office lease of this year — nationwide — Meta has rented 719,000 square feet at a campus located near the corner of Crossman Avenue and Caribbean Drive in northern Sunnyvale that also fronts on East Java Drive.

In a separate transaction that points to significant expansions for Meta, the tech company leased 520,000 square feet in Burlingame on Airport Boulevard in a project known as Peninsula Innovation Point.

The Sunnyvale rental deal becomes a big-time win for Tishman Speyer, a veteran developer that just seven months ago bought the campus, which features four buildings and enticing open space amenities.

“We are pleased that Meta has chosen Tishman Speyer and our Sunnyvale campus,” said Rob Speyer, chief executive officer of Tishman Speyer.

Newmark commercial real estate brokers Phil Mahoney, Michael Saign and Jon Mackey represented Tishman Speyer in the leasing deal, which Tishman Speyer said it believes is the largest commercial real estate lease in the nation during 2021.

“I can confirm that we signed new leases in Burlingame and Sunnyvale that total more than 1 million square feet,” said Chloe Meyere, a spokesperson for Meta. “These offices will help support our employees’ evolving workforce needs.”

Tishman Speyer’s Sunnyvale campus features an array of amenities, including a gym with a basketball court, lockers, showers, an outdoor volleyball court, executive briefing center, a full-service cafeteria, multiple kitchens, break centers, phone rooms and other common areas.

Meta’s mega lease in Sunnyvale counters gloomy predictions that tech companies would flee Silicon Valley and that tech firms intended to focus on letting employees work from home rather than return to their offices.

“Silicon Valley remains the global center of innovation and its importance will continue to grow even as other innovation hubs emerge,” Speyer said.

It was only last April that Tishman Speyer bought the four-building Sunnyvale campus from NetApp, paying the tech company $365 million for the complex, which includes a parking garage.

NetApp had decided shift its headquarters to a big office building in San Jose’s Santana Row.

At the time, some experts raised fears that Tishman Speyer was taking a huge risk purchasing an office complex that would quickly become empty with NetApp’s departure. Others warned that companies were reluctant to return to offices and wouldn’t require big buildings like the ones Meta leased.

Instead, Tishman parlayed its gambit into one of the biggest leasing triumphs of the year.

“We were always convinced that the tech sector would maintain a strong appetite for high-quality collaborative spaces,” Speyer said.

Mahoney, an executive vice chairman with Newmark, believes that while tech companies may establish outposts in other states, Silicon Valley remains the place they want to be.

“Tech companies are voting with their feet and showing that they want to stay in Silicon Valley,” Mahoney said.