Jump Trading, one of the most active proprietary trading firms operating on US stock exchanges, has taken up new office space in the heart of the Square Mile, where it has doubled headcount over the past year.

Jump Trading International, the firm's European subsidiary, has increased headcount to 25 this year, according to people familiar with the situation. This has been done through selective hiring and the transfer of resources from the US, they added. The group's latest filings with Companies House show that the firm employed 10 staff at the end of 2011.