Magners will remove its sponsorship of the Celtic League at the end of the current season, it has been announced.
The Irish cider firm, which has supported the competition for the last six years, is said to be moving on to explore other opportunities.
"Magners will not be renewing their sponsorship of the Celtic rugby competition at the end of their current contract," a league spokesperson told the BBC. "The sponsorship has come to its natural end."
A new sponsor is expected to be revealed soon, car firm Fiat being among the rumoured potential benefactors.
The league comprises four Welsh, four Irish, two Scottish and - as of the current season - two Italian teams. It is used by the Welsh, Irish and Scots to determine European qualification.