But the need to recruit and retain qualified workers is paramount, Serot adds. And the big four tech regions are tapped out. “Tech firms have no choice but to look to other cities.” Austin has the world-renowned University of Texas, and the Chicago region has a set of highly-regarded schools, including Northwestern University, the University of Chicago, the University of Illinois, and many others, and all feed their graduates into growing labor pools. “There is a lot going on that makes sense for the Google's of the world.”

Chicago has also become a far more attractive place to live. New and sparkling residential towers have risen in new neighborhoods such as West Loop and South Loop, all of which provide the kind of urban lifestyle most favored by millennials. And the affluent suburbs on the North Shore can provide homes to the older executives with families.

Each city in the US has unique aspects, and those qualities govern where firms decide to expand, according to Colin Yasukochi, director of research and analysis for CBRE in the San Francisco Bay Area. “By expanding into other markets, these tech firms can tap into new and potentially lucrative business opportunities clustered in other markets, such as media and entertainment in Los Angeles or machine learning and cyber security in Washington, DC.”

“We expect large tech companies to continue to expand outside their headquarters markets,” he adds, “including further into secondary and even tertiary markets—particularly as space availability in top tech submarkets continues to tighten, driving rents up. Large tech company expansion into smaller markets will help foster innovation clusters, further boosting job creation and creating additional office demand.”