Back in August, when the move was first announced, Facebook told GlobeSt.com it may ultimately decide to maintain some Downtown office space to cover any overflow. "While the new building is large enough to hold all of our current employees, it may not be adequate to keep all of us together until we find a permanent headquarters," a spokesperson said. "To prepare for this contingency, we expect to retain some of our current space in downtown Palo Alto as well."

The company now tells GlobeSt.com that its plan "is to sublease all of the space we currently have in Downtown Palo Alto," though it declined to detail its leaseholds. Local industry sources tell GlobeSt.com that 25,000 square feet of the company's Downtown space has already been subleased and that an additional 60,000 square feet remain available. Rod Sherba and Jack Troedson of Cornish & Carey have the sublease assignment; they declined comment.

Facebook reportedly has leaseholds in as many as 10 different downtown buildings, but according to local industry sources the vast majority of its space is in five buildings: 31,000 square feet at 164 and 285 Hamilton Ave., 25,000 square feet 151 and 156 University Ave., and 13,000 square feet at 500 Emerson St. Facebook reportedly leased as much as 100,000 square feet downtown but has let some short-term leases run out in advance of the move.

Palantir Technologies, which is headquartered around the corner at 100 Hamilton, has subleased Facebook's space in both University buildings. The company offers platforms for integrating, visualizing, and analyzing information that are employed by the intelligence, defense, and law enforcement communities as well as hedge funds and financial institutions. Palantir COO Alex Moore tells GobeSt.com that the growing company acquired the leasehold to meet "increasing customer demand" and that it will be retaining its leasehold at 100 Hamilton.

Facebook is a five-year-old social networking website with more than 200 million users worldwide. Its headquarters consolidation is an interim step while it seeks a corporate campus of its own. The move "positions us well to continue looking for a long term campus solution while also allowing employees to work together as much as possible," a company spokesperson tells GlobeSt.com.

Stanford Research Park is a 700-acre, 10-million-square-foot development on land owned by Stanford University. The park is home to 162 buildings housing approximately 150 companies that are predominantly scientific, technical and research oriented.

Facebook's soon-to-be new home base is a former Hewlett-Packard building that later housed HP-spinoff Agilent. Located at 1601 California Ave., the property is slated for a housing redevelopment under a 2005 agreement between the city and Stanford University.

A leasing flyer for the building last year, when the lease was signed, said it could be leased through mid-2013. The asking lease rate was $1.25 per square-foot per month (NNN). Doug Beck, Jim Fletcher and Matt Germino represented Stanford University in the transaction. The asking sublease rates for Facebook's available Downtown spaces range from a high of $4.95 per square-foot (NNN) at 500 Emerson to a low of $3.50 per square foot (NNN) for its space in 164 Hamilton.