The Sun says on top of the massive three-year wage deal for Ronaldinho, City owner Thaksin Shinawatra will also have to stump up £20m to buy the Brazilian playmaker from Barca.
But the former Thai prime minister hopes much of his outlay will be recouped in commercial deals.
In a year at the Eastlands helm, Shinawatra has spent £50m on players and sacked Sven Goran Eriksson - despite him getting the club into Europe.
New boss Mark Hughes has been told there is a lot of cash to spend this summer.
City's offer for Ronaldinho dwarfs the Premier League's current biggest pay deals.