Where: Cupertino, on land formerly owned by Hewlett-Packard.
What: A new headquarters of 2.8 million square feet for 12,000 Apple employees.
Apple Chief Executive Tim Cook: "We think this will be the most collaborative work environment anywhere. It's going to be incredible."
Where: Santa Clara, across the street from its current headquarters.
What: A new headquarters consisting of two triangular buildings, each with 500,000 square feet for as many as 4,000 employees.
When: July 2015 (first building)
CEO Jen-Hsun Huang: "Its vast open floors will facilitate our cross-functional work. The nature of building our products requires experts from multiple disciplines to come together, and this building is designed above all for collaboration."
Where: Menlo Park
What: A 433,555-square-foot West Campus for 2,800 engineers.
When: spring 2015
CEO Mark Zuckerberg: "The idea is to make the perfect engineering space: one giant room that fits thousands of people, all close enough to collaborate together. It will be the largest open-floor plan in the world, but it will also have plenty of private, quiet spaces as well."
Where: Mountain View
What: A new Bay View complex of nine buildings totaling 1.1 million square feet.
David Radcliffe, a civil engineer in charge of real estate at Google: "You can't schedule innovation. We want to create opportunities for people to have ideas and be able to turn to others right there and say, 'What do you think of this?'"
Where: north San Jose
What: A new U.S. headquarters for its semiconductor division, with 680,000 square feet for 600 employees.
Chris Goodhart, a Samsung spokeswoman: "We make some of the most innovative components that are going into the latest consumer and IT products. So the campus should reflect that."