At the moment, it is all theory and estimation: Nobody knows which of the short-term changes to office use brought about by the pandemic will stick, and which will fade away if and when the coronavirus retreats.

But a report from real estate research firm Green Street Advisors has attempted to quantify the impact of increased working from home on office landlords in the U.S. and Europe. The numbers don’t make pretty reading.

Green Street predicted that office demand in developed economies could drop by 10% to 15% as a result of working from home. Its thesis: The trend toward greater flexibility and employees working from home more often will prove long-lasting, but the move toward de-densification will be reversed (albeit not totally) in a post-coronavirus world. The net result for office landlords: tenants needing more space.

There is increasing evidence that companies will allow, indeed encourage, employees to work from home more regularly than they do today.

Goldman Sachs said recently that only about 15% of its London workforce had returned to the office, a figure broadly similar for its locations across the globe. Far from impacting profitability, a fortnight ago the firm reported its best quarterly earnings figures in almost a decade, far exceeding analyst expectations.