Boxing: Forbes reveals Mayweather's 2015 earnings will shatter all-time record for an athlete's annual pay

Unbeaten US boxing champion Floyd Mayweather's 2015 earnings would shatter the all-time record for a sportsman's annual pay, thanks to his highly awaited May 2 but with Filipino boxer and politician Manny Pacquiao, according to Forbes' calculations.

Forbes noted that Mayweather would likely to earn at least 150 million dollars and Pacquiao more than 100 million dollars for the welterweight world title showdown in Las Vegas.

The financial news website said that payouts could be higher still if more than three million pay-per-views are sold, Sport24 reported.

Forbes also revealed that Mayweather's haul would represent the highest yearly earnings ever by an athlete, surpassing former world number one golfer Tiger Woods' inflation-adjusted record of 125 million dollars in 2008.

Woods currently occupies both first and second place on Forbes' list of all-time highest paid athletes in a given year, adjusted for inflation, with his adjusted earnings of 120 million dollars in 2009 number two on the list.

The golfer is followed by NBA legend Michael Jordan, with inflation-adjusted earnings of 115 million dollars in both 1997 and 1998. Woods' 113 million dollars in 2007 and 2010 are next.

The highest boxer on the list is former heavyweight world champion Mike Tyson, with inflation adjusted earnings of 112 million dollars in 1996, the report added.