We ran the 2026 Open Championship 100,000 times — a market-anchored Plackett-Luce field model over the 156-player field — and read off the distribution. Scheffler is the clear favourite at 15.8% to win, 60% to make the top-5; McIlroy is next at 8.8%. The field of 146 others holds 43.3% — golf's honest variance over 72 links holes, which is exactly why no single player is priced above ~20%.
Market-anchored (Scheffler +400, McIlroy +800, Rahm +1200, Fleetwood +1400, DeChambeau +1600, de-vigged) Plackett-Luce over the 156-player field. McIlroy 8.8% win; the 146-player field 43.3% — golf's genuine variance. The win odds track the book; the top-5/top-10 split is the simulation's read.
We simulate the tournament 100,000 times and lock the resulting distribution. Scheffler is the clear favourite, but golf's defining feature — a deep field and high variance over 72 holes — means the most likely single outcome is that someone outside the top names wins (the field at 43.3%).
| Player | P(win) | P(top-5) | P(top-10) |
|---|---|---|---|
| Scottie Scheffler | 15.8% | 60.0% | 86.0% |
| Rory McIlroy | 8.8% | 39.7% | 67.4% |
| Jon Rahm | 6.0% | 29.2% | 53.9% |
| Tommy Fleetwood | 5.3% | 25.9% | 48.8% |
| Bryson DeChambeau | 4.7% | 23.3% | 44.6% |
| Field (146 others) | 43.3% | — | — |
Each simulated tournament draws every player's performance as strength + Gumbel noise (a Plackett-Luce ordering) and ranks the leaderboard. Strengths are anchored to the de-vigged BetMGM outright market (Scheffler +400 … Hovland +2800) plus a 146-player field bucket. The win probabilities therefore track the book; the top-5 and top-10 numbers fall out of the ordering. Golf's high variance is built in — and is why the favourite sits at ~16%, not the 50%+ a dominant world No.1 commands in match-play sports.
Verified 2026-06-21: 154th Open, Royal Birkdale (Southport), 16–19 July; 156-player field; Scheffler defending champion. Sources: BetMGM outright odds + The Open field.
Scheffler at 15.8% is the rational favourite, but the single most probable outcome on this board is a winner from outside the named ten (43.3%). That is not a hedge — it is the structural truth of a 156-player major on a links course, where weather waves and one hot week routinely lift a longshot. Our lock surfaces that honestly rather than over-betting the favourite.
The simulator is a committed, fixed-seed script (scripts/sim/the-open-2026.py) — 100,000 parallel tournaments, deterministic. We synthesise and calibrate public signals (the outright market); we do not claim a proprietary golf model. Scored by Brier against the official Open result.
Scheffler runs away with it — if the world No.1 wins comfortably, our 15.8% looks light (though he's still our top single name). A pure longshot wins — vindicating the 43.3% field read. Either way the distribution is scored honestly against the leaderboard.
RAOSCAFF locks P-19 on 2026-06-21, before the July 16 start at Royal Birkdale. The simulator is committed for reproducibility. We score the locked win + top-5 distribution by Brier against the official Open Championship result.
Fixed seed, committed script, deep-field variance built in — the leaderboard, simulated and checkable.