The prediction market for the total number of upsets in the 2026 NCAA Men's Basketball Tournament's Round of 64 has repriced significantly, shifting consensus toward a much higher final tally. The move was triggered by a string of underdog victories during Thursday's opening day of games. Probabilities for nine or more upsets have surged, with the contract for "9+ upsets" jumping 62.0 percentage points to 83.0%. This reflects a broad market belief that the first-round chaos will continue through Friday's slate of games.
The market utilizes a laddered structure where outcomes are not mutually exclusive (e.g., a result of 10 upsets also resolves "9+ upsets" and "8+ upsets" as YES). By analyzing the price differences between these contracts, we can infer the market's view on specific outcomes. The current pricing implies a 41.0% probability of exactly nine upsets, with a 22.0% chance of exactly 10, making the 9-10 upset range the new market consensus.
Distribution Analysis
The probability gains were concentrated in the upper range of potential outcomes. Contracts for "8+ upsets" through "12+ upsets" all saw sharp increases in probability, reflecting a market reacting in real-time to the confirmed results from the first 16 games of the round. The highest volume trading occurred in contracts predicting eight or more upsets.
| Outcome | Current Prob | Change (24h) | Volume (24h) |
|---|---|---|---|
| 5+ upsets | 99% | +8.0pp | 33,287 |
| 6+ upsets | 99% | +15.0pp | 84,751 |
| 4+ upsets | 99% | +1.0pp | 9,742 |
| 7+ upsets | 98% | +34.0pp | 99,333 |
| 8+ upsets | 91% | +53.0pp | 114,835 |
| 9+ upsets | 83% | +62.0pp | 113,881 |
| 10+ upsets | 42% | +33.0pp | 78,254 |
| 11+ upsets | 20% | +17.0pp | 77,727 |
| 12+ upsets | 8% | +6.0pp | 64,030 |
| 13+ upsets | 3% | +2.0pp | 18,261 |
| 14+ upsets | 2% | +1.0pp | 6,952 |
| 15+ upsets | 1% | ~0pp | 2,193 |
| 16+ upsets | 1% | ~0pp | 166 |
| 20+ upsets | 1% | ~0pp | 37 |
What's Driving the Shift
The sharp upward repricing appears to be a direct reaction to the results from Thursday, March 19, the first of two days in the Round of 64. A series of upsets involving double-digit seeds provided a clear catalyst for the market shift.
At least six upsets were confirmed on Thursday, rapidly increasing the baseline for the tournament's final total [3]:
- No. 12 High Point stunned No. 5 Wisconsin 83-82 [2]. The go-ahead layup came with just 11.2 seconds left, marking the school's first-ever NCAA Tournament win [4].
- No. 11 VCU erased a 19-point second-half deficit to beat No. 6 North Carolina 82-78 in overtime [5].
- No. 11 Texas defeated No. 6 BYU 79-71, with the Longhorns controlling the game for nearly its entirety [1].
- No. 10 Texas A&M secured a 63-50 victory over No. 7 Saint Mary's, aided by a stifling defense that produced 12 steals [1].
- No. 9 Saint Louis won decisively against No. 8 Georgia, 102-77 [3].
- No. 9 TCU edged No. 8 Ohio State in a tight 66-64 contest [3].
These results, particularly the wins by three teams seeded 11th or lower, provided concrete data points that moved the market's expectations for the final upset count significantly higher ahead of Friday's 16 remaining games.
Market Context
Historically, first-round upsets are a defining feature of the NCAA Tournament. The high frequency of certain underdog victories provides a statistical basis for expecting several such outcomes each year.
According to historical data since the tournament expanded in 1985, No. 12 seeds defeat No. 5 seeds about 33.8% of the time, while No. 11 seeds beat No. 6 seeds nearly 37.0% of the time [8]. The matchups between No. 10 and No. 7 seeds are even closer, with the No. 10 seed winning 40.0% of the time [8].
Thursday's results, which included one 12-over-5 upset and two 11-over-6 upsets, align with these long-term historical trends. The concentration of these probable-yet-unpredictable events on a single day appears to have convinced traders that this year's tournament is trending toward a higher-than-average number of total first-round upsets, prompting the sharp price adjustment. Even games that were not upsets, such as No. 16 Siena's competitive 71-65 loss to top overall seed Duke, may have contributed to a market sentiment favoring underdogs [7].
What to Watch
The final number of upsets will be determined by the slate of 16 games scheduled for Friday, March 20 [2]. Several of these matchups feature the seed pairings that are historically prone to upsets, including No. 12 seeds UNI and Akron facing No. 5 seeds St. John's and Texas Tech, respectively [2].
Analysts had also flagged several of Friday's games as potential upsets ahead of the tournament, including No. 11 Miami (Ohio) over No. 6 Tennessee and No. 10 UCF over No. 7 UCLA [9]. The market will resolve based on the final results of all 32 first-round games as reported by ESPN, Fox Sports, and the NCAA [2].
