Facebook is quietly laying the foundation for its own HQ2-style expansion by leasing enough office space in Seattle for 20,000 employees

Ryan C Slimak Photo

Facebook will have 850,000 square feet in a development in Bellevue, Washington, a city just east of Seattle.

• Facebook leased a large building in a Seattle suburb, and now has nearly 3 million square feet in the area, the company confirms.
• The Seattle area is already the company's largest engineering outpost - with this lease secured it has enough space for an estimated 20,000 employees in the region, total.
• That's about the same number of people that Facebook employs on its home turf, the San Francisco Bay Area.
• Facebook has 5,000 employees in the Seattle area now, but this move lays the groundwork for a massive expansion in the region.
• Facebook is among the tech giants seeking large swaths of office space in the Seattle area, as the rush for talent and real estate in Silicon Valley only gets more competitive. Google and Apple are expanding there, too.
• Click here to read more BI Prime stores

Facebook signed a lease for a large building in a Seattle suburb, Business Insider has learned, cementing the Seattle area as the company's largest engineering outpost.

The Menlo Park, California-based company leased a 325,000-square-foot building called Block 6 in a 36-acre development known as the Spring District in Bellevue, WA, according to public records and a source in the area's commercial real estate industry.

With this deal locked down, Facebook has enough space for an estimated 20,000 employees in the Seattle area. For perspective, Facebook has 43,000 employees worldwide, and about half of them are in the San Francisco Bay Area, the social network's home turf.

Facebook confirmed the lease and said the company has more than 2.7 million square feet across 18 offices in Seattle, Bellevue and Redmond (where Microsoft makes its home). Facebook said it has now 5,000 employees in the Seattle area - though this move would seem to indicate that it plans to hire much more, given that it now has enough room in the region for 20,000 employees using the industry standard estimate of 150 square feet per employee.

"This represents our investment in continued growth in the greater Seattle region," a Facebook spokesperson told Business Insider. "We continue to source available expansions to accommodate our growth both in Seattle and Bellevue. The Seattle area is a dynamic and competitive real estate market and we always want to keep our options open as we grow in the region."

Facebook is among the Silicon Valley giants seeking large swaths of office space in the Seattle area, even as it becomes ever more expensive to acquire both real estate and talent in California, where both are at a perpetual shortage.

Bellevue, for its part, is also where companies including Amazon and Microsoft have large offices, representing a major center of expansion for the tech giants. Even Amazon, headquartered in Seattle proper, is gobbling up enough real estate in Bellevue to rival its so-called HQ2 campus development. Now, it appears, Facebook is laying the groundwork for its own, similar expansion.

Cost of living has become such a problem in the San Francisco Bay Area that Apple on Monday said it was committing $2.5 billion to help alleviate the California housing crisis. Facebook and Google have also pledged money.

Meanwhile, in the Seattle area, Facebook already has large offices right near Amazon's famed Day One tower headquarters in the city proper, as well as a massive presence for its Facebook Reality Labs and Oculus virtual reality subsidiaries in Redmond.

Google has a large and expanding presence across the region, as well, spanning Seattle and the nearby city of Kirkland, while Apple recently announced plans to take over a large campus just blocks away from Amazon's headquarters.

Facebook has 247 open positions in Seattle listed on the company's website at the time of this writing, but it's unclear how many employees it plans to hire for each position.