There are no women among the world’s 100 top-earning sports stars for the first time since Forbes began compiling the list.
Tennis champion Serena Williams was the only female to appear in the standings last year but dropped out after a spell on the sidelines following her pregnancy.
Forbes said its rankings of highest-paid athletes have “long been testosterone-heavy”.
But the magazine added that “there has always been at least one female athlete, and as many as three, who qualified since the list was expanded to at least 50 names in 2010. Not this year.”
Serena Williams made her Grand Slam comeback last month at Roland Garros after giving birth.
Boxer Floyd Mayweather Jr reclaimed his place at the top of the list with earnings of $285m (£212.8m) after his big-money fight with Conor McGregor last August.
The retired undefeated champion – whose nickname is Money – reached the summit for the fourth time in seven years.
Lionel Messi and fellow footballer Cristiano Ronaldo, who was top for the previous two years, were second and third respectively.
The Barcelona and Argentina star was paid $111m (£82.9m), while the Real Madrid and Portugal forward took home $108m (£80.7m).
Conor McGregor was fourth in the list
UFC fighter McGregor was fourth in the rankings with $99m (£74m).
Formula One driver Lewis Hamilton was the UK’s highest earning athlete in 12th, with $51m (£38.1m).
The figures include all prize money, salaries and bonuses earned between 1 June 2017 and 1 June 2018.
Here is the top 10:
1 – Boxer Floyd Mayweather, $285m (£212.8m)
2 – Footballer Lionel Messi, $111m (£82.9m)
3 – Footballer Cristiano Ronaldo, $108m (£80.7m)
4 – Mixed martial arts fighter Conor McGregor, $99m (£74m)
5 – Footballer Neymar, $90m (£67.3m)
6 – Basketball player LeBron James, $85.5m (£63.9m)
7 – Tennis player Roger Federer, $77.2m (£57.7m)
8 – Basketball player Stephen Curry, $76.9m (£57.5m)
9 – American Football player Matt Ryan, $67.3m (£50.3m)
10 – American Football player Matthew Stafford, $59.5m (£44.5m)