Do prediction markets and sportsbooks agree on the Spurs’ chances?
Polymarket favors the Spurs, while sportsbooks back the Thunder. Predictbook compares NBA title odds and what the differences mean.
The NBA season begins on October 20, and opening night features two teams that many expect to fight for the title.
Polymarket has already picked a narrow favorite between the San Antonio Spurs and Oklahoma City Thunder. Its 2027 NBA Champions market, one of the deepest in the sport with more than $23 million traded, prices the Spurs at 22% and the Thunder at 20%. The New York Knicks are back in third at 11%.
Traditional sportsbooks see it slightly differently, with DraftKings having the Spurs and Thunder dead level at +270 each. FanDuel went further and made Oklahoma City its outright favorite.
Converting odds to probabilities, +270 implies about a 27% chance. However, this figure includes the sportsbook's margin. Eliminating that margin brings the two teams' sportsbook-implied chances into the low-to-mid 20s, close to Polymarket's current position.
Where sportsbooks differ from prediction markets
The real disagreement is the order of the favorites, not the size of the odds. Polymarket separates the Spurs from the Thunder, while the sportsbooks have them level or lean toward Oklahoma City.
There's a recent case for Polymarket's view, as the Spurs beat the Thunder in a seven-game Western Conference final last season before losing to the Knicks in the Finals. Victor Wembanyama is still improving, and San Antonio's young core of Stephon Castle and Dylan Harper is only getting better.
Oklahoma City's counterargument is continuity and experience. Shai Gilgeous-Alexander has won the last two MVP awards, and the Thunder won the title in 2025.
Predictbook's read is that the two markets are closer than they look. The headline gap between 22% and +270 mostly reflects the bookmaker's margin.
We lean toward Polymarket, as the Spurs have already beaten their main rival in a seven-game series. That deserves a slight edge going into the new season. The bigger point is that because prediction markets don't have the same built-in margin, backing either favorite on Polymarket offers a cleaner price than what you get at a sportsbook.
Opening night won't settle the debate, but it's the first real data point of the season. Expect the gap between these two markets to move quickly on Polymarket if either team makes a statement on Tuesday.
This page does not constitute investing advice. Prediction markets and/or gambling may result in loss of funds. You are advised to conduct your own due diligence before taking any action.
