Bale has struggled at Real Madrid over the past 18 months and has been linked with a switch back to England.
Manchester United, Chelsea and Tottenham have been linked with the Wales superstar.
But bookmakers Paddy Power have now been forced into drastic action after a huge bet was placed Bale moving to United.
They have slashed the odds, performing a ‘monster plunge’, to 1/2 on for the transfer to happen.
A Paddy Power spokesman said: “Jose Mourinho clearly needs a bail out this season, and it looks like he’s getting that with a Bale in.
“We have seen crazy numbers on this transfer taking place over the last 24 hours, forcing the traders to perform a monster plunge on the odds of Gareth Bale arriving at Old Trafford in January.”
Bale’s time in Madrid started with a bang as he scored in the Champions League final in his first season to help them win their 10th European Cup.
And he has since won two more as well as La Liga last season.
But his influence has waned due to injuries and patience is running out from the fans and the board.
Florentino Perez is plotting a major overhaul over the next six months and Bale could be one of those dumped to help fund it.
Manchester United are keen on a deal and Jose Mourinho publicly admitted they would try and sign him last summer if a deal could be done.
But he stayed put and has struggled again this season, making just six La Liga appearances.
His substitute appearances for the final 18 minutes in the 3-0 defeat to Barcelona was his first in La Liga since the end of September.
And Real have struggled in his absence falling to fourth in the league and now trailing Barcelona by 14 points having played one game fewer.
Real have been linked with Neymar, Kylian Mbappe, Harry Kane and Mauro Icardi as they look to overhaul their attack with time also running out on Karim Benzema and Cristiano Ronaldo’s Madrid careers.
Perez is ready to fund a big spend next summer as they look to overhaul Barcelona again.
