The Six Nations has announced that it has entered into partnership with CVC Capital Partners, which will see the private equity and investment advisory firm take a one-seventh share.
The IRFU along with the English, French, Scottish, Welsh and Italian unions will retain a sixth-sevenths (85.7%) share, with CVC Fund's investment totalling up to £365 million (€425.5m) with the aim of launching "ambitious growth plans" for the men's, women's and Under-20s championships as well as the Autumn International Series.
In a joint statement, Six Nations Rugby said: "Under the terms of the agreement the six unions will retain sole responsibility for all sporting matters as well as majority control of commercial decisions.
"The CVC Fund VII investment into Six Nations Rugby will be paid to the six unions over a period of five years, reflecting the long-term nature of the partnership.
"This capital investment, combined with the expected growth of the tournaments, will help the unions to support the development of rugby at all levels in their respective territories over the years ahead."
Commenting on the development, IRFU CEO Philip Browne described it as "very positive news" for Irish rugby.
But he added that in the context of significant financial losses caused by the impact of the Covid-19 pandemic, "in real terms the initial funds received from this deal will simply deliver the funding required to keep Irish rugby going for little more than a month".
"Importantly, under the agreement, Unions retain complete control of all sporting matters while all commercial and broadcast decisions, which will benefit from CVC's commercial and marketing expertise, also requires majority Union approval," he said.
"The IRFU, together with our fellow Five Unions, is phasing its sale of equity to CVC, with payments materialising over the next five seasons. The total capital proceeds to Irish Rugby, if the deal is approved, will be up to Stg£48m (€55.96m) over this period, with approx. Stg £6m (€7m) net of costs due when the deal closes, later this year. It is also expected that annual long-term revenues from the Six Nations will increase."
Browne added that "the real benefit of this agreement will come into effect in future years".
Six Nations Rugby CEO Ben Morel said: "This is a hugely positive development and I want to express my thanks to all parties involved. In particular, our six unions and federations, for the strong sense of unity and collaboration they have shown throughout this process to create a unified Six Nations Rugby and agree the partnership with CVC."
It is CVC's latest investment in rugby. In 2020, the Guinness Pro14 confirmed that it had entered into a partnership with the firm who took a 28% share of the competition from Celtic Rugby DAC.
They had previously taken a 27% stake in Premiership Rugby, England's top flight league in 2018.
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