LONDON - Total prize money on the ATP tour will surpass $100 million for the first time in 2015.

The ATP says prize-money increases on the World Tour will rise steadily over the next four years and reach $135 million by 2018.

The biggest increase will come in the top-tier Masters 1000 tournaments, with an overall 14-per cent hike over the next four years.

Prize money for the 250 category will increase by an average of 3.5 per cent during the same period.