Public documents, like lawsuits or tax liens, can give you an idea of a tenant's help, as can trade publications covering whatever industry they're involved in, said speakers here at the Building Owners and Managers Association's annual Office Building Show at a session entitled "Recognizing and Managing Tenant Financial Distress."

"It's out there," said Tara Gorman, an associate at Washington DC-based law firm Greenberg Traurig. "You just have to look."

There are other things a landlord can do to physically assess the health of a tenant. Gorman suggested counting how many people come out of an office during a fire drill. It also doesn't hurt to make sure the name of the entity on your lease is the firm's most updated name and still exists. "If you see people walking through the front lobby with a plant, that's a good sign someone is leaving," she said.