Silverstone is due to host the British GP next July
The race's future is to be discussed at a meeting of motor racing's governing body, the FIA, on Friday following concerns over traffic access and facilities.
But Mosley, president of the FIA, hinted on Tuesday that Silverstone may get the go-ahead for its 7 July date.
"It sounds encouraging and Octagon (British Grand Prix organiser) will have a full opportunity to show their plans on Friday," Mosley said.
Octagon Motorsports, which has a 10-year deal to promote the event, intends to use the money to improve traffic flow and car parking at the Northamptonshire circuit.
That came after suggestions from sources within the FIA last week that the race might be dropped because of the organiser's continuing failures to sort out the facilities.
An FIA source was quoted on Reuters news agency on Tuesday saying that following threats to run the British GP as a non-championship race, Octagon may have done enough to save the race.
"It has gone from being evens to probably being reasonably in their favour," the source said. "It is quite possible they will retain it. It looks like we have finally got their attention at last.
"It looks like at long last people are beginning to see the circuit has serious problems and that we are serious if they don't improve."
Improving access
Octagon had previously announced a £40m plan to upgrade Silverstone in conjunction with the the track's owner, the British Racing Drivers' Club, and F1 owner Bernie Ecclestone.
However, it decided to announce the additional funds on Monday, just days before the FIA delivers its decision.
It hopes the plans - which include improving access roads, circuit entrances and car parking, as well as introducing a park and ride scheme - will counteract past criticisms of the British Grand Prix.
Octagon Motorsports chief executive Rob Bain said: "The £10.6m investment is already well under way and we have always placed emphasis on improving facilities for public access to Silverstone.
"Since we announced our plans ahead of this year's Grand Prix, all parties have agreed to revise the masterplan, so as to give greater emphasis to the substantial improvements relating to both access and parking."
Octagon plans to add to existing lanes around the circuit and to improve the flow of traffic to and from the Silverstone bypass, which is under construction.
As well as improving internal access and traffic flow, Octagon said it intended to manage traffic flow to and from the circuit better.
"We are determined to ensure that the investment pledged by all parties will secure Silverstone's future within international motorsport," Bain added.
The FIA is believed to be losing its patience with Silverstone over its long-standing traffic problems.
An FIA source is quoted in the Guardian newspaper saying: "It's always jam tomorrow with Silverstone, but the only jam they seem capable of producing is a traffic jam."
Octagon is hoping to attract government funding to assist with its plans, but FIA president Max Mosley said he "wouldn't feel at all comfortable asking for public money for work on the circuit itself or its infrastructure".