Rugby's Pro14 announced on Friday it had agreed to sell a 28 percent stake in the five-nation league to CVC Capital Partners as the private equity firm expands its investment into the sport.
The agreement, worth a reported £120 million ($A223 million), will provide a much-needed financial boost to the Pro14's unions and clubs during the economic crisis caused by the coronavirus.
The Pro14 competition, which brings together sides from Italy, Ireland, Wales, Scotland and South Africa, has been indefinitely suspended since March.
CVC, which formerly owned a controlling stake in Formula One, bought a 27 percent stake in the English Premiership in 2018.
Talks have also reportedly been held over the acquisition of a 15 percent stake in the Six Nations championship.
"CVC's show of faith has been impressive and is in keeping with their proven track record of success when it comes to sports investment, including Formula 1, MotoGP and Premiership Rugby," said Martin Anayi, CEO of Pro14 Rugby.
"This partnership allows all of our stakeholders to plan for a sustainable period of growth, which will benefit the fans, the players and the game."
As part of the deal, the Italian Rugby Federation will join the unions of Ireland, Scotland and Wales as owners of the Pro14 and receive a share of the CVC investment.
"It is to the credit of everyone involved that the deal is now over the line and we look forward to a sea change in the ability of the Pro14 to realise its full potential," said Welsh Rugby Union chief executive Martyn Phillips.
"This investment is great news for our teams and for Welsh rugby as a whole, although we are under no illusions that COVID has and will continue to have a significant impact on our organisation for some time.
"The Pro14 is a cross-border competition which brings unique challenges in the current climate, but this is a ringing endorsement for the recent evolution of the competition."