And the practice has not yet infiltrated all aspects of UBS’s business.

The trading floors at UBS in London still have a more traditional setup, with groups of employees heading to the same set of desks each day to view three or six screens of trading data.

But that could change in the future. “The trading desk is our next port of call to achieve user mobility,” Ashley Davis, managing director for the UBS corporate center in London, said.

By having a more mobile setup for its employees, UBS believes it is able to use its real estate more efficiently. The company is using a ratio of one available desk for every 1.2 employees who work in the new building in London.

More than 6,000 people will ultimately work there; about 89 percent have moved in so far.

There are common areas where employees can gather for meetings or work if the company finds itself at full desk capacity. Most days, however, someone is traveling or on vacation.

UBS executives insist the shift is not all about costs.

“I would be wrong to sit here and say there isn’t an economic efficiency dimension,” Mr. Owen said. “In and of itself, that’s not the reason to do it. It would fail on that basis. It has to be of value to our staff and our structure in the way we operate. There has to be a value there.”

UBS spent two years preparing workers in London for the new mobile desk concept and addressing their concerns, Mr. Owen said.

The new metal-covered office building, designed by Ken Shuttleworth of Make Architects, had to overcome a variety of challenges to fit into the neighborhood.