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McGregor secured a lucrative £15.6m payday from his devastating second-round TKO defeat to Dustin Poirier at UFC 257 in January.
The future UFC Hall of Famer made the rest of his astonishing earnings from the sale of whiskey brand 'Proper Twelve' and also through his ever-growing endorsement portfolio.
Barcelona captain Messi finished behind McGregor with a whopping £92.4m earnings, while Juventus superstar Ronaldo came third with £85.3m earnings.
Now, McGregor took to social media to thank Forbes for "recognising my role as an entrepreneur."
The Notorious tweeted to his 8.7m followers: "Baby we did it!! Uimhir a Haon.
"Thank you Forbes for recognizing my role as an entrepreneur! It was a dream to lead this list with so many successful athletes! Onwards and upwards we go."
According to Forbes, McGregor followed in the footsteps of Roger Federer and Tiger Woods to become only the third athlete to earn more than £49.8m off the field in a year while still active in their respective sport.
The publication said: "Adding in his endorsements, McGregor made $158m [£112.3m] outside of his fighting career over the last 12 months, becoming only the third athlete, after Roger Federer and Tiger Woods, to earn more than $70m [£49.8m] off the field in a single year while still actively competing."
Dallas Cowboys quarterback Dak Prescott (£76.4m) and Los Angeles Lakers superstar LeBron James (£68.6m) finished fourth and fifth respectively in the rich list.
McGregor's No 1 position on the highest earners even led to a clip from 2016 resurfacing online as the Irish star told Ronaldo he would catch him on the rich list.
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