Golfer Rory McIlroy made history as one of only six golfers in the modern era to complete the Grand Slam, winning the four major championships. While McIlroy's win was good for the sport of golf and his legacy, it may prove to be a negative for sports betting companies.
What Happened: McIlroy won his first ever Masters Tournament in a playoff with Justin Rose in the 2025 tournament, that unlike last year, didn't feature the same fanfare with Tiger Woods not participating.
While viewership for media partners Walt Disney Co (NYSE:DIS) and Paramount Global (NASDAQ:PARA)(NASDAQ:PARAA) may have been down in the first few days of the Masters on a year-over-year basis without Woods, the final Sunday round provided ups and downs for golf fans and bettors that could make this one of the most memorable Masters tournaments in years.
For McIlroy it now serves as the final piece needed to complete the career grand slam, winning the Masters, PGA Championship, U.S. Open and British Open. McIlroy previously finished second at the Masters in 2022 and had multiple top 10 finishes before his victory Sunday.
The victory didn’t come easy with McIlroy having multiple ups and downs Sunday and giving away his final round lead multiple times, as shown on the Kalshi prediction market odds below.
With the win, McIlroy now joins Gene Sarazen, Ben Hogan, Gary Player, Jack Nicklaus and Tiger Woods as the only Grand Slam winners in golf.
Read Also: Tiger Woods, Rory McIlroy, PGA Tour, SoFi Prep ‘Golf Remixed’ For 2025 TGL Launch
Sportsbooks Suffer: Several sportsbooks may be on the hook for large payouts on McIlroy, who was among the most bet golfers to win the Masters at odds mostly in a range of +650 to +1,200 before the tournament began Thursday.
At William Hill, the British sportsbook had a Money Back offer for a Free Bet if McIlroy won. This turns into a seven-figure payout by the sportsbook for the promotion, according to the company.
"Masters Sunday 2025 will go down as one of the most dramatic we've ever seen, but also as one of the most significant in the history of betting on golf for William Hill," company spokesperson Lee Phelps said.
Phelps said McIlroy was the biggest liability for the sportsbook with tens of thousands of individual bets placed on the golfer to win the Masters.
At BetMGM, which is a joint venture between MGM Resorts International (NYSE:MGM) and Entain, McIlroy was one of the most bet golfers to win. BetMGM's John Ewing said 19% of the money was on McIlroy to win the tournament ahead of the fourth round on Sunday.
What's Next: While McIlroy has now completed the career grand slam, bettors look ready to wager on the 35-year-old winning more major tournaments going forward.
BetMGM offers betting on how many majors McIlroy will win in 2025, with the upcoming PGA Championship (May 15-18), U.S. Open (June 12-15) and British Open (July 17-20). The payouts are
- 1: -200
- 2: +188
- 3: +1,400
- 4: +8,000
No golfer has won all four majors in the same year in the modern era, with Woods coming close and winning three of the four in 2000 followed by a Masters win in 2001 for four consecutive major wins.
Bettors are also already backing McIlroy to win the 2026 Masters, according to Ewing. With odds of +1,200 at BetMGM, 59% of the money is on McIlroy to win back-to-back Masters tournaments.
Prediction market Kalshi also has betting odds for the remaining three majors in 2025, where McIlroy is either the favorite or has the second-best odds behind Scottie Scheffler in each tournament as listed below:
- U.S. Open: McIlroy 12%, Scheffler 15%
- PGA Championship: McIlroy 17%, Scheffler 16%
- British Open: McIlroy 13%, Scheffler 20%
Kalshi said it made history with fans in all 50 states live trading the Masters tournament predictions. A total of $86 million was traded on the Masters on Kalshi, which was three times more than on the Super Bowl.
Read Next:
- More Than A Game: Athlete’s Rare, Emotional Interview Reveals Human Side Of Professional Golf
Photo: Debby Wong via Shutterstock
