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How accurate are the ATP US Open odds?

The closing prices of 1,055 finished games since Tue 24 Aug 2021, set against what happened: the chance the market gave, with the bookmakers' margin removed, next to how often it came in. A record of what the market did, not a tip.

The market's record

1,055 games, 2 bookmakers
  • Closing favourite won 70% 741 of 1,055 games
  • Market Brier score 0.384 0 is perfect; a coin flip scores 0.500
  • Average closing payout 94.4% 100% minus the bookmakers' margin
  • Games covered 1,055 Tue 24 Aug 2021 to Sun 13 Sep 2026

44 of the 1,099 games finished in that time are left out: no bookmaker had a closing price on every outcome.

Market chance against what happened

0-10% chance: happened 4.1% of 97 selections 10-20% chance: happened 13.4% of 172 selections 20-30% chance: happened 29.6% of 233 selections 30-40% chance: happened 35.0% of 280 selections 40-50% chance: happened 43.0% of 265 selections 50-60% chance: happened 56.6% of 281 selections 60-70% chance: happened 65.0% of 280 selections 70-80% chance: happened 70.4% of 233 selections 80-90% chance: happened 86.6% of 172 selections 90-100% chance: happened 95.9% of 97 selections 100% 0%
Market said 0%100%
Happened
Market chancePriceSelectionsMarket saidHappenedDiff
0-10% 10.00 or longer 97 6.8% 4.1% -2.7 pts
10-20% 5.00 to 10.00 172 15.6% 13.4% -2.2 pts
20-30% 3.33 to 5.00 233 25.4% 29.6% +4.2 pts
30-40% 2.50 to 3.33 280 35.2% 35.0% -0.2 pts
40-50% 2.00 to 2.50 265 44.9% 43.0% -1.9 pts
50-60% 1.67 to 2.00 281 54.8% 56.6% +1.8 pts
60-70% 1.43 to 1.67 280 64.8% 65.0% +0.2 pts
70-80% 1.25 to 1.43 233 74.6% 70.4% -4.2 pts
80-90% 1.11 to 1.25 172 84.4% 86.6% +2.2 pts
90-100% 1.11 or shorter 97 93.2% 95.9% +2.7 pts

Every priced outcome of every game is one selection. "Market said" is the bookmakers' average implied probability with the margin removed; "Happened" is how often that outcome came in. On the diagonal the market was right on average; above it, that kind of result happened more often than the prices said. Bands with fewer than 30 selections are left out.

Home, away

OutcomeMarket saidHappenedDiff
Home win 50.3% 48.6% -1.7 pts
Away win 49.7% 51.4% +1.7 pts

The market's average closing chance for each outcome over all 1,055 games against the share of games it won. "Home" is the first-named side.

Bookmaker accuracy

lower is better
BookmakerGamesBrier scorevs market averagePayout
Unibet 768 0.375 -0.003 94.6%
Bet365 886 0.385 +0.006 94.5%

Each bookmaker's own closing prices, margin removed, scored against the results of the games it priced; "vs market average" compares it with the bookmakers' average on the same games, so a negative figure means its prices were the closer. Bookmakers with fewer than 50 priced games are left out. Differences of a few thousandths are noise; a much higher score usually means the bookmaker's last price was captured well before the start, so it is the price in our archive being scored, not the trader.

Odds accuracy FAQ

How accurate are ATP US Open odds?
Across 1,055 finished ATP US Open games since 2021, the closing favourite won 70% of the time. The market's closing chance, with the bookmakers' margin removed, gave the home side 50.3% on average and home wins happened 48.6% of the time. The bands above show the same comparison price by price: a well-calibrated market has outcomes happening about as often as its prices say.
What is a Brier score?
The squared distance between the chances a bookmaker's prices gave and what happened, averaged over games: 0 would be perfect foresight, and on a three-way market a coin-flip price scores 0.667. The market average's closing prices score 0.384 in this league; the lowest single bookmaker is Unibet at 0.375. Differences of a few thousandths between bookmakers are noise, not skill.
Does a well-calibrated market mean the odds cannot be beaten?
Calibration says the market is right on average, not on every game. A band where outcomes happened more often than the prices said is where the closing market under-priced that kind of result over these seasons. The bookmaker's margin, about 5.6% here, still has to be cleared: the closing line value calculator shows what a price needs to beat.