Shares in three Nordic paper giants rally on merger rumors.

• Trading in Stora Enso halted amid merger rumor

Trading was on Thursday halted for shares in Europe's biggest paper maker Stora Enso and two other Nordic paper giants, amid reports that the three companies would partially merge. The stock exchanges in Helsinki, Oslo and Stockholm said they had suspended trading of Stora Enso, Holmen and Norske Skog -- one of the world's biggest newsprint producers -- pending announcements later in the day.

However, Store Enso announced later the same day that no discussion were ongoing between the three companies.

"Stora Enso confirms that there are no discussions ongoing concerning the matter mentioned in [Finnish newspaper] Helsingin Sanomat", the paper maker said.

Norske Skog said that it's "willing to contribute" to a restructuring of the industry but "does not wish to comment speculations and rumors about strategic processes".

Before trading stopped, Norske Skog saw its share price soar more than 20 percent on the Oslo bourse, while Stora Enso and Holmen had been up more than 4.0 percent.