The swift emptying of commercial space marks a sharp departure from the real estate market that boomed in New York, Chicago and other cities in recent years.
A weak commercial real estate market can mean layoffs among its estimated 3.6 million workers and at companies providing goods and services to real estate firms.
Still, some real estate experts and landlords see this as just another boom-and-bust cycle, although the bust is happening at lightning speed.
That will determine how rapidly the real estate market recovers.
And while some of the changes in commercial real estate could be permanent, Calanog expects the overall market to do what it always does recover.