John Fredriksen's big new investment in tanker rival Euronav is probably a financial punt on markets improving, one leading analyst believes.

The tanker tycoon's privately controlled CK Limited was revealed to have amassed a 5.5% slice of the Belgian VLCC and suezmax company on Monday, a stake already worth $123m.

"This will likely lead to merger speculation between Frontline and Euronav," said Clarksons Platou Securities managing director Frode Morkedal.