Saturday's 2-0 victory over QPR at Loftus Road means the 12-times Premier League champions are now unbeaten in their last 15 league matches and sit 15 points clear at the top of the table.
It's 8/11 for Sir Alex Ferguson's men to go on and win the league by 12 or more points.
"With Manchester United 15 points clear at the top of the table and 11 matches still to play, you have to ask yourself, how many points will United go on to win the league by?" said Coral's Tim Reynolds.
"Man United still have to play Man City, Arsenal and Chelsea before the end of the season so it wouldn't be a surprise to see United to drop a few points."
Elsewhere in the Premier League, Arsenal's 2-1 victory over Aston Villa means the Gunners are now only one point behind fourth place Tottenham, who play West Ham on Monday.
It's 4/5 for Arsenal to finish the season in the top four (8/11 Tottenham top four) and 3/10 for their manager Arsene Wenger to still be at the Emirates on the opening day of the 2013/14 season (9/4 that he leaves).
QPR are now 1/9 from 1/6 with William Hill to be relegated and Reading 1/3 from 4/9 after their home loss to Wigan.
Villa are now in the third relegation spot and are 8/11 from 5/6 to go down.
"Things are looking very bleak for QPR, Reading and Villa but Wigan might just be safe for another year," said spokesman Rupert Adams.