The family is interested in selling the club.
The club's American owners are willing to listen to offers for the club. US investors will likely purchase the club if it is sold.
The process will consider a number of options, including new investment into the club, a sale or other transactions involving the company, according to a Manchester United statement.
Sky News had previously reported that the Glazer family were about to formally announce their intention to explore potential sources of outside investment that could include a full-blown auction of the club.
Investment bankers were instructed by United's owners to advise on the process, according to sources.
According to a football finance expert, Manchester United's share price immediately rose by 17 percent, adding almost $400m to the club's market value.
The Board of Directors of Manchester United, one of the most successful and historic sports clubs in the world, has begun a process to explore strategic alternatives.
The ultimate goal of the process is to position the club to take advantage of opportunities both on the pitch and commercially.
All strategic alternatives, including new investment into the club, a sale, or other transactions involving the company, will be considered by the Board. Expansion of the club's commercial operations on a global scale will be assessed in the context of enhancing the long-term success of the club's men's, women's and academy teams.
Executive Co-Chairmen and Directors, Avram Glazer and Joel Glazer said: “The strength of Manchester United rests on the passion and loyalty of our global community of 1.1 billion fans and followers. As we seek to continue building on the Club’s history of success, the Board has authorized a thorough evaluation of strategic alternatives. We will evaluate all options to ensure that we best serve our fans and that Manchester United maximizes the significant growth opportunities available to the Club today and in the future. Throughout this process we will remain fully focused on serving the best interests of our fans, shareholders, and various stakeholders.”
The Raine Group is the exclusive financial advisor of the Company.
Rothschild and Co. is the exclusive financial advisor to the shareholders.
No assurance can be given that the review will result in a transaction. Unless and until the Board approves a specific transaction or other course of action, Manchester United will not make any further announcements.
The announcement of a review of financial options that could include a sale process would mean an end to years of speculation over the future of the club.
After the retirement of Sir Alex Ferguson, United haven't won the title in three years.
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The club became involved in a legal fight with the player over an interview in which he questioned United's ambition and lambasted the club's approach to owning it.
On Tuesday, United announced that they had lost a player.
The family that took control of United in 2005 may not sell.
A partial sale to new investors is one of the possible outcomes from the process.
New infrastructure investment and substantial funds are required to enable the men's team to compete at the top of the European game, while the stadium needs to be transformed into a genuinely world-class venue.
During Tuesday's trading session on the New York Stock Exchange, United's share price implied a market cap of over $2 billion.
Reports in recent months have said that any transaction would need to be worth between £5 billion and $9 billion to convince the owners to sell.
A minority stake in the company was listed by the Glazers in 2012 but they retained complete control through a dual class share structure.
For more than 18 months, the club promised to introduce a small supporter ownership scheme that would give fans the same voting rights as the Glazers.
Despite a promise to have it operational by the start of the season, the initiative is yet to be launched.
It was one of the commitments made by the co-chairman in the wake of theESL debacle.
Within hours of the official launch, the project collapsed due to public and political acrimination.
Fans of United forced the postponement of a home match against their rivals after protesting against the ESL and the Glazer family.
'Love United, hate the Glazers' has become a familiar refrain during their tenure, with supporters critical of a perceived lack of investment in the club's infrastructure while the owners have made hundreds of millions of pounds from their continued commercial success.
The identities of potential buyers will be the focus of the sale process.
Sir Jim Ratcliffe, the Ineos billionaire who has supported United since childhood, said in August that he was interested in buying the club.
The kind of takeovers seen at Paris Saint-Germain andNewcastle United will be linked to bids from billionaires from around the world.
The Red Knights, a group led by a former United director, could revive an attempt to take control of the club, according to reports.
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The prospective sale of Manchester United comes at a time when the owner of the club is weighing the sale of all or part of the club.
It would be the first time in history that simultaneous sale processes for two of English football's so-called 'big six' would take place.
The timing suggested that some investors believed the value of top clubs could be approaching its peak against a backdrop of tough global economic forecasts.
The shifting financing of the global football industry is highlighted by the United's announcement during the World Cup.
Sky sports reporter Ben Ransom is working.
The fact that the Glazers have always said that they are committed to the future of the club is a huge development.
Two American ownership models potentially looking to move the clubs on is a pretty remarkable moment.
It's an insight into how they perceive the future and potential future difficulties of challenging at the top of the premier league