Roger Federer and Caroline Wozniacki already have a considerable lead over their respective counterparts when it comes to prize money in 2018.
Federer continued his career renaissance that began last year by winning his 20th Grand Slam at the Australian Open in January when he defeated Marin Cilic in the final over five sets.
Meanwhile, Wozniacki won her first Grand Slam title when she defeated Simona Halep over three sets to emerge victorious in Melbourne Park.
The duo each earned $4m AUD (£2.25m, $3.1m) for their winning efforts which has played a major role in them leading the Tour in terms of prize money.
Federer also went on to earn an additional €401,580 (£356,326) after becoming the oldest world number one in tennis history at the Rotterdam Open which he went on to win last month by defeating Grigor Dimitrov in the final.
In total, the 36-year-old Swiss has earned a grand sum of $3,656,655 (£2,657,949) in the calendar year so far with the closest earner being current world number three Cilic, who has a total of $1,631,735 (£1,186,075).
|1. Roger Federer||$3,656,655|
|2. Marin Cilic||$1,631,735|
|3. Hyeon Chung||$745,796|
|4. Kyle Edmund||$714,926|
|5. Grigor Dimitrov||$615,195|
Hyeon Chung, who upset Novak Djokovic at the Australian Open and eventually reached the semi-final comes in at third. Fellow surprise semi-finalist Kyle Edmund follows just behind the South Korean with Dimitrov rounding out the top five.
In the women's singles, Wozniacki has a total of $3,225,104 (£2,344,263) with Halep coming just behind her with a total of $1,841,498 (£1,338,548). Elina Svitolina, Angelique Kerber and Petra Kvitova complete the rest of the top five.
|1. Caroline Wozniacki||$3,225,104|
|2. Simona Halep||$1,841,498|
|3. Elina Svitolina||$1,211,593|
|4. Angelique Kerber||$1,058,569|
|5. Petra Kvitova||$785,644|
With lucrative events such as the BNP Paribas Open in Indian Wells and the Miami Open all coming up later this month, one can expect the earnings to drastically change.