The largest shareholder in OMX has given the management and executive of the Nordic exchange a vote of confidence, asserting they will honour their duty to shareholders after it emerged Nasdaq's bid to buy the European exchange included perks for OMX bosses which could bias them against the rival offer by Borse Dubai.

A spokesman for Investor AB, which holds 10.7% of OMX stock, said today: "To look after the interests of shareholders is their mission and I am sure they will do that. OMX shareholders and management still have to figure out which deal is the best for OMX."