The Norwegian Competition Authority is to investigate the planned merger between Norwegian stock exchange Oslo Børs and national securities depository VPS.
Following on-off negotiations over the past few years, Oslo Børs and VPS agreed in March this year to merge their respective operations.
But in today's statement the two parties say that they have received notification from the Norwegian Competition Authority that it "may intervene against the merger".
Oslo Børs and VPS say they submitted a complete notification of the merger to the competition watchdog on 11 May. The competition authority has 70 days from that date to decide whether to intervene in the merger process.