Manchester United supporters spearheaded by a group calling themselves the Red Knights are poised to table a £1.25bn bid for the club by June that will involve fans owning a majority stake.

Under proposals being studied by the bidder's financial adviser, Nomura, around 30 wealthy Red Knights investors would take control of United by setting up a new company that would later invite fans from around the world to subscribe to new shares.

The structure of the bid is designed to wrest control of United from the US Glazer family as quickly as possible and to meet legal requirements that determine how firms can be run under collective ownership. "The takeover would be in two stages but the objective is to give the fans a central role in the club's future," said a City source.

Jim O'Neill, Goldman Sachs's chief economist, who is one of the founding members of the Red Knights, is keen to distribute equity as widely as possible among millions of supporters globally.

The idea is for United to resemble Spanish rival Barcelona, which is owned by its fans and where profits are ploughed back into the club. At the moment, United's profits are having to be used to service huge debts drawn down by the Glazers when they acquired United in 2005.

Barcelona relies on the same revenue streams as British clubs, but experts say its model could be adopted by Premiership teams with a strong sense of their own identity.

Japanese bank Nomura last week met with wealthy supporters of the Red Knights campaign, which is backed by investment banker Keith Harris and Paul Marshall, founder of London-based hedge fund Marshall Wace. The man in charge of negotiations is Guy Dawson, who set up financial advisory boutique Tricorn before it was recently acquired by Nomura.

Dawson has already held talks with the Manchester United Supporters Trust (Must) to demonstrate that the Red Knights are serious about giving fans a major say in how United is run.

Duncan Drasdo, Must's chief executive, said: "We want a big stake in the club although the exact size will depend on any take-up of shares in the event that supporters are invited to subscribe to new equity."

Drasdo adds: "It's important that as much of the debt is paid down as quickly as possible so that the club has maximum headroom to invest in new players and to ensure affordable ticket prices."

As a symbol of opposition to the Glazers, Must has been encouraging fans to forsake United's traditional red colours and wear green and gold scarves – the colours of the club, then known as Newton Heath, until 1902.

But a spokesman for the Glazers, who reiterated that the family had no intention of selling, said: "There is no dress code printed on the tickets, people are entitled to wear what they like. The important thing is that they show their support for the team."

Drasdo said "the amount of money flowing out of club to service the Glazers' £700m debt pile is quite astonishing. "United needs to invest a lot of money in new players in the next couple of years as well as eventually find a replacement for manager Sir Alex Ferguson. He is going to be a very hard act to follow and his successor will not come cheap."

United's chief executive, David Gill, has defended the Glazers, saying that funds are available for Ferguson to use in the transfer market this summer. Gill maintains the £80m received last year from the sale of Cristiano Ronaldo to Real Madrid is still part of the club's budget. Gill said: "The money from Ronaldo is sitting in the bank account."

Sources close to the Red Knights say that offers of financial support continue to pour in, with several sovereign wealth funds expressing an interest. Five British individuals are said to be willing to invest £10m apiece. It is understood they have also won the support of former United chairman Sir Roy Gardner.