Fresh speculation that industrial gas and forklift manufacturer Linde could be bought by rivals caused its share price to increase more than three per cent to a six-year high this week.

Reuters reported that by 9:51am GMT, on Tuesday, the stock was up 2.6 per cent at EUR60.80 after hitting an earlier high of EUR61.25, the highest since August 1999. It was also the top gainer in the DAX, which was up 0.5 per cent.

Traders linked the gains to a Boersen-Zeitung newspaper report that said Linde's main shareholders, Allianz, Deutsche Bank and Commerzbank, might sell their stakes.

"The story is very vague but it's enough to renew speculation," a Frankfurt trader said.

Linde spokesperson Uwe Wolfinger said the German news report was a general story on Linde's shareholder structure.

"...very old speculations and nothing new," Wolfinger said.

The media has speculated that Linde could merge with British gas manufacturer BOC and sell its forklift unit (Forkliftaction.com News #180).