New owners could be in place by the end of the season.
The process is not subject to the same restrictions that were in place for the sale of Chelsea.
If the Glazers sell, a deal is likely to be done by the spring, according to the sources.
In May 2005, the Glazers bought United.
The majority of the money spent by the club has gone to the Americans.
Since the failed attempt to launch the European Super League there have been widespread supporter protests.
It is thought that unpopularity will be an advantage in the sales process as unpopularity is seen as a once-in-a-lifetime opportunity to buy one of the world's most well-known sporting organisation.
If the price is correct, a sale will be concluded. The New York Stock Exchange's valuation of United at the close of trading on Tuesday was $3.65 billion.
urgent work on the club's stadium would need to be funded by the new owners.
The idea of building a new stadium has not been ruled out, but the Glazers prefer to improve the current one. The club's home since 1910 is considered to be part of its brand value.