Nasdaq OMX has suffered from a decline in its market share in the Scandinavian region – where it operates four stock exchanges – in marked contrast to other European bourses, as it faces increased competition from rival venues.

Nasdaq's stock exchanges in Sweden, Finland, Denmark and Iceland have seen their combined market share in equities trading fall from 58.2% at the start of the year, to 56.1% in September, according to data from Thomson Reuters. Its Stockholm market has suffered the biggest single drop, from 40% to 37.6%, the data showed.