Professional tennis is one of the most lucrative sports with global appeal, which is why tennis superstars are making a ton of money these days.

Prize money may not be the largest income sources for tennis stars who are consistently ranking, but Grand Slam titles are still curial in securing million-dollar endorsements.

There's a ton of money not just in professional tennis but also to the endorsements, exhibitions, and appearances related to the business. Here is the list of the top 5 richest tennis players.

Pete Sampras
Age: 43 Net Worth: $150Pete Sampras is an American former professional tennis player for 15 years and was ranked no. 1 for six years in a row. Reuters
Serena Williams
Age: 33Net Worth: $100 The world no. 1 was born in Saginaw, Michigan and currently holding 17 Grand Slam titles. REUTERS
Rafael Nadal Avenges Loss to Rosol
Age: 28 Net Worth: $100The current world no. 2 born in Manacor, Spain is regarded as the finest clay court player in history of tennis. REUTERS
Roger Federer of Switzerland celebrates after defeating Marinko Matosevic of Australia following their mens singles match at the U.S. Open tennis tournament in New York August 26, 2014.
Age: 33 Net Worth: $300 millionRoger Federer is a Swiss born professional tennis player born on August 8th, 1981 in Basel, Switzerland to parents Robert and Lynette. The 17-time Grand Slam champion began playing tennis at a very early age. REUTERS
Andre Agassi of the U.S. returns a ball during an exhibition match against Gustavo Kuerten of Brazil in Rio de Janeiro, December 11, 2010.
Age: 44 Net Worth: $175Andre Agassi is an American retired professional tennis player and former world no. 1 was born in Las Vegas, Nevada. Reuters