Moody's Analytics has been conducting a series of analyses on commercial real estate and surrounding problems with varying degrees of focus on office. So, for example, moderate changes in cap rates and cash flows could cause big problems for the property class. And then the firm the percentage of buildings in major metros — 31% on average (with wide variations) — that are old enough to be considered at least borderline obsolete.

This week, Moody's examined the question of commute times. "While many factors can affect the vacancy rates of metros, such as economic, employment, and population changes, we continue to hear chatter that firms are more reluctant to maintain/expand space in metros where employees have greater difficulty getting to the office," they wrote.

"In an era where employees still have a bit of an upper hand in the remote work debate, any additional cost of coming to the office could be quite important to utilization rates, and ultimately to office sector performance," Moody's continued. "In a simple analysis, we tackle this issue by observing a metro's time to work data, as measured by the Census Bureau's American Community Survey, in relation to our Moody's Analytics CRE vacancy rate data."