The Saudi government's entertainment arm said on Twitter that Mushref Al-Ghamdi, general manager of real estate group AqarOne, was the highest bidder for a "Beyond Imagination" ticket.
The winner will attend Thursday's match in Riyadh featuring a combined team from Saudi clubs Al-Nassr - who recently signed Ronaldo - and Al-Hilal versus Messi's Paris St Germain in the duo's first on-pitch meeting since Juventus beat Barcelona 3-0 in December 2020.
Winning bidder Al-Ghamdi will attend the winner's ceremony after the match, enter the dressing rooms, and meet the two players who for years have vied to be the world's greatest.
Though revenue from the auction will go to charity, the event could also fuel accusations of "sportswashing" by Saudi Arabia - distracting attention from rights abuses by splashing money on sport.
As well as attracting Ronaldo, Saudi Arabia have signed up Messi as a tourism ambassador. PSG is owned by the Qatari government, which has just staged the World Cup.
