The Six Nations has "entered into an exclusive period of negotiation" with private equity firm CVC to sell a stake in rugby's oldest championship.

The deal will provide a financial boost to each union but would mean partly surrendering control of the competition.

"Six Nations believes that investment in rugby football is vital for the long-term future of our game and this belief is central in our decision to enter into this period of negotiation," said a Six Nations statement.

"Six Nations, together with its constituent unions and federations, has agreed to enter into an exclusive period of negotiation with an external investor partner.

"As these negotiations are confidential and commercially sensitive, Six Nations will not be making any further comment."

The Six Nations unions - England, Ireland, Scotland, Wales, Italy and France - have been in talks for almost two years over pooling their commercial interests.

In March, BBC Sport reported that CVC's initial offer was for an approximate 30% share in the Six Nations. However, according to the Times, the latest proposal would see CVC take control of 15% of the unions' collective commercial arm.