Technical glitches have delayed trading on the Stockholm, Helsinki and Copenhagen stock exchanges for the second time this week.
The exchanges, which are operated by Nasdaq-owned OMX, have failed to open on time for the second day running.
In a brief statement on its Web site OMX says today's opening is postponed until 12:00 Central European Time (CET) "due to technical disturbances".
The glitch - which also delayed market opening yesterday - is thought to be caused by problems with an upgrade of the Saxess trading system.
The problem has also affected the Oslo Børs, which uses the Saxess platform.
In a statement on its site, Oslo Børs says: "The problems with Saxess Trading System continues today. The opening of the equity market, bond market, Oslo Axess and ABM will today be postponed until 12:00."
Update
OMX pushed back opening of the Stockholm, Helsinki and Copenhagen exchanges to 13:30 CET due to the on-going technical problems.