Man Utd shares fall amid rumours Glazers could scrap sale plan
The family also expects the investment to help them double the value of the club over the next 10 years, ESPN reported, citing a source.
Manchester United did not immediately respond to a Reuters request for comment.
The Glazers began looking at options including new investment or a potential sale of the club in November, 17 years after they bought the 20-time English champions for 790 million pounds.
US private equity firm Carlyle Group Inc was in talks about a "major" investment as the auction of the Premier League soccer club entered its final stages, Sky News reported on Saturday.
A small portion of the club's shares is listed on the New York Stock Exchange. The market capitalisation was about $3.6 billion as of Friday's close.