Barclays has begun using devices with heat and motion sensors to track when staffers are at their desks, according to Bloomberg.
Barclays investment bankers in London recently began spotting the OccupEye black boxes, made by UK firm Cad-Capture, strapped to their desks.
However, in a statement to Bloomberg, the bank insists that the technology is not being used to spy on workers but rather to assess office space usage.
"This sort of analysis helps us to reduce costs, for example, managing energy consumption, or identifying opportunities to further adopt flexible work environments," says Barclays.
Unite the union was informed of the move and says that it will monitor the situation to ensure staff are not spied on. Lloyds says that it uses similar technology.