A major Middle Eastern investor in Plus Markets is seeking to oust the exchange's chairman and bring its former chief executive back to the board.
At the request of Amara Dhari Investments, Plus will call a general meeting to vote on the removal of Giles Vardey, the chairman.
Amara bought 17 per cent of Plus in 2009 but is unhappy about the company's direction. Plus has struggled as the number of companies on its main exchange has tumbled.
Amara wants to return Simon Brickles to the board. He ran Plus from 2004 and stepped down last year.
The investment vehicle voted against Mr Vardey's re-election to the board at Plus's annual meeting in June.