Bats Chi-X Europe, the operator of Europe's largest share trading platform, is to lose of one its most senior London executives, Financial News has learnt.

Paul O'Donnell, chief operating officer for Bats Chi-X Europe and a former Morgan Stanley executive, resigned on June 8, the firm said. O'Donnell is planning to move with his family back to the US, where, according to Bats, he will rejoin Morgan Stanley as a managing director in New York.