The Financial Conduct Authority (FCA) is warning people to beware of people posing as investment advisers and offering to help them set up new schemes via online meeting platforms.
They ask their victim to share the screen and enable remote access – which hands over control of their device and, potentially their bank account.
About 2,100 cases have been reported to the FCA since July 2020.
More than £25m was stolen in the 15 months from January 2021.
The FCA said the number of screen-sharing scams it had seen had risen 86% to 683 in the six months from July to December 2021 compared with 367 for the same period the year before.
Screen-sharing has become a familiar part of work life, as people use popular online meeting programmes in their jobs.
Remote access software is a legitimate tool for services like IT support to troubleshoot problems without being in the room.