National Bank Open Odds: 25 Seeds Gone, Shelton Still Alive
Updated August 9, 2026 · 11 min read · by Jake Hari
The Quick Answer
National Bank Open odds on Kalshi have two players level at the top of the board: Ben Shelton at 22.5 cents and Rafael Jodar at 22, half a cent apart, with the same 23-cent ask on both. Seven AI models scored all eight remaining contracts without being shown a single price, and they flatly reject that tie. The panel puts Shelton at 28.3% and Jodar at 13.0%, a 15.3-point gap between two contracts the market prices as near-equals. Shelton is the defending champion of this tournament and one of only two men left who has ever won a Masters 1000 event. Jodar is 19 years old, has one career title, and it came on clay. The full board, every model's number, and the quarterfinal that decides most of this are below.
New to Kalshi event markets? Start here.
All prices in this piece were read from Kalshi on August 9, 2026, and are quoted as the midpoint between the bid and the ask. This market resolves within days rather than months, so the numbers move fast while the tournament is on court, and the page is re-priced as it does. One caution on reading any quote here between sessions: the book on this event is a cent or two wide, so a midpoint can drift half a cent without much changing behind it. The bid and the last traded price are the steadier reads, and the top two contracts have both traded at 23 cents.
One note before the board. The eight open contracts sum to 103.5 cents, not 100. That three-and-a-half-cent excess is the board's overround, and it is small enough that the raw prices here sit very close to the normalized probabilities they imply. The comparisons below use the de-vigged figure, which is the price divided by 1.035.
The Board
| Player | Quarterfinal | Market | Panel blend |
|---|---|---|---|
| Ben Shelton | vs Jakub Mensik | 22.5¢ | 28.3% |
| Jakub Mensik | vs Ben Shelton | 16.5¢ | 15.4% |
| Learner Tien | vs Daniel Merida | 11.5¢ | 15.0% |
| Rafael Jodar | vs Arthur Fils | 22¢ | 13.0% |
| Arthur Fils | vs Rafael Jodar | 16.5¢ | 11.3% |
| Brandon Nakashima | vs Luciano Darderi | 8.5¢ | 10.0% |
| Luciano Darderi | vs Brandon Nakashima | 2.5¢ | 4.7% |
| Daniel Merida | vs Learner Tien | 3.5¢ | 2.4% |
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Every Seat's Number
| Player | Market | Claude Fable | Claude Opus | Claude Sonnet | GPT | GLM | Kimi | DeepSeek | Blend |
|---|---|---|---|---|---|---|---|---|---|
| Ben Shelton | 22.5¢ | 28.0 | 27.5 | 29.3 | 27.5 | 26.0 | 25.5 | 34.3 | 28.3% |
| Jakub Mensik | 16.5¢ | 15.0 | 15.0 | 14.3 | 15.5 | 16.5 | 16.0 | 15.3 | 15.4% |
| Learner Tien | 11.5¢ | 15.0 | 14.5 | 15.2 | 15.0 | 14.5 | 14.0 | 16.5 | 15.0% |
| Rafael Jodar | 22¢ | 13.5 | 14.0 | 12.1 | 14.5 | 11.5 | 14.5 | 10.6 | 13.0% |
| Arthur Fils | 16.5¢ | 11.5 | 11.5 | 11.5 | 11.5 | 12.5 | 11.0 | 9.8 | 11.3% |
| Brandon Nakashima | 8.5¢ | 9.0 | 9.5 | 9.8 | 9.5 | 11.5 | 10.5 | 10.3 | 10.0% |
| Luciano Darderi | 2.5¢ | 5.0 | 5.0 | 5.6 | 4.0 | 5.5 | 5.5 | 2.5 | 4.7% |
| Daniel Merida | 3.5¢ | 3.0 | 3.0 | 2.3 | 2.5 | 2.0 | 3.0 | 0.8 | 2.4% |
Every seat on this panel is graded against real market settlements, records to date: Claude Fable 82% on 450 graded calls · Claude Opus 84% on 514 graded calls · Claude Sonnet 82% on 498 graded calls · GPT 83% on 3,225 graded calls · GLM 81% on 2,307 graded calls · Kimi 83% on 2,285 graded calls · DeepSeek 80% on 2,332 graded calls. Recomputed daily; the full scoreboard is public.
These are model estimates, not predictions of fact and not financial advice. Every number in this piece gets graded in public once the market settles, on the full graded scoreboard.
Seven of the panel's eight seats scored this board. Each one saw the same fetched data card and no price at all, then read the other six anonymized boards and revised.
More live boards from the same panel: US Open men's champion, where Jannik Sinner leads at 52¢ and Rafael Jodar is already 4¢ · US Open women's champion, where Aryna Sabalenka sits at 28¢ · Ballon d'Or 2026, where Harry Kane leads at 58¢. Prices fetched August 9, 2026.
Free: The Weekly PM Market Brief — the 8-model panel's graded record, the week's biggest market-vs-model gaps, and what's spiking next. One email, Sundays.
The Market Card
The event is KXATP-26MONTRE on Kalshi. Every contract on it reads the same way, with only the name changing: "If Jakub Mensik wins the 2026 ATP Montreal professional tennis tournament, then the market resolves to Yes." A second clause covers withdrawal: if a player forfeits, withdraws from consideration, or takes any official action that removes him from being able to win, his contract resolves No.
The board is a clean partition, which is rarer than it sounds. Kalshi listed 46 players when the draw began. Thirty-eight of those contracts have already resolved No as their players lost, leaving eight open, and those eight are exactly the men still capable of winning. There is no Field or Other contract, and there does not need to be one.
The listed close of September 13 and the expected expiration of August 30 are both placeholders that fall well after the tournament ends. The clause that actually governs is the exchange's early-close condition, quoted verbatim: "This market will close and expire after a winner is declared."
Kalshi contracts are CFTC-regulated event contracts, not sportsbook wagers, and trading is 18+. Availability varies by platform and location.
Ben Shelton: The Defending Champion In The Hardest Quarter
Shelton is the highest-ranked man left at ATP No. 10, the fifth seed, and the only player in the field who has won this tournament. He beat Karen Khachanov in three sets to take the 2025 title, which remains his only Masters 1000 win. He is 23, left-handed, and has six career titles from a 128-82 record at tour level.
His route here has been the cleanest on the board. He beat Jenson Brooksby 6-3, 7-5, then Zizou Bergs 6-3, 6-2, then Joao Fonseca 6-3, 7-6. Three matches, no sets dropped, one tiebreak.
The reason he sits at 28.3% rather than 40% is the draw. His quarterfinal is against Jakub Mensik, the only other man left with a Masters 1000 title, won at Miami in 2025. Six of the seven seats named that match as the biggest uncertainty on the board, and several priced it close to a coin flip. GLM put it at 58/42; DeepSeek, the most bullish seat on Shelton at 34.3%, put it at 63/37.
The panel's read is that Shelton is the best player in the field and has the worst path through it. Those two facts roughly cancel, which is how a defending champion ends up at 28% rather than as a runaway favorite.
Rafael Jodar: Where The Panel Fights The Market Hardest
Jodar is the market's co-favorite at 22 cents and the panel's fourth choice at 13.0%. Nothing else on this board splits that far.
The case for him is this week. He beat Corentin Moutet in three sets, then took out Lorenzo Musetti, the 11th seed and ATP No. 13, 6-4, 6-3. Then he beat Jiri Lehecka, the eighth seed and ATP No. 12, 6-3, 6-3. Two top-13 players in straight sets is the best stretch of tennis anyone in this field has produced. He is 19, and his ranking of No. 15 is a career high set on August 3.
The case against him is everything before this week. He has one career title and it came on clay. His only hard-court final ended in a loss, leaving him 0-1 on the surface this tournament is played on. His full tour-level record is 32-12, which is a small sample by the standards of the men he is now expected to beat.
Every seat applied that discount, though not equally. GPT and Kimi were the most generous at 14.5%. DeepSeek was the most severe at 10.6%, and stated its reason plainly: his only career title is on clay and he is 0-1 in hard-court finals.
There is a structural point underneath the disagreement. Jodar's quarterfinal is against Arthur Fils, and the market prices Fils at 16.5 cents. Between them the market is spending 38.5 cents on a single quarterfinal that only one man survives. The panel spends 24.3%.
Jakub Mensik: The Panel's Second Choice And The Market's Joint Third
Mensik is the quietest number on the board, and the one the panel and the market agree on almost exactly: 16.5 cents against a 15.4% blend. He is 20, seeded 13th, and won the 2025 Miami Open, which makes him one of two Masters 1000 champions left standing.
His route has been less emphatic than Shelton's. He dropped a set to the qualifier Jacob Fearnley in the second round, winning 6-3, 3-6, 6-3, then beat Terence Atmane 7-5, 6-4 and Botic van de Zandschulp 6-4, 7-5.
What makes him interesting is not his own number but what it implies about Shelton's. Kimi held Mensik above most of the panel at 16.0 and explained why in one line.
I held Mensik above most peers: Miami 2025 on hard makes his QF nearly a coin-flip, and whoever wins it becomes title favorite. — Kimi
That is the cleanest statement of the board's structure available. The Shelton-Mensik winner is the favorite for the title. The other six contracts are, in effect, priced on the chance that somebody other than the Shelton-Mensik winner lifts the trophy.
Dark Horses The Panel Won't Dismiss
Brandon Nakashima (8.5¢, 10.0% blend). The panel is above the market on the 28th seed, and the reason is surface. Of the six men whose pages publish a finals breakdown, Nakashima is the only one whose tour-level finals have all come on hard courts, where he is 1-3. He is also drawn into the softest quarterfinal in the bottom half. GLM was highest on him at 11.5%, rewarding him specifically for getting Darderi in the last eight. He earned his place the hard way, beating Arthur Rinderknech 7-6, 5-7, 7-5.
Luciano Darderi (2.5¢, 4.7% blend). The panel prices him at more than double the market despite applying a heavy discount, and the discount is the story. All five of Darderi's career titles and all seven of his tour-level finals came on clay. He has never reached a final on a hard court. Every seat marked him down for it, and he still cleared the market price, because he is ATP No. 22, he has already won three matches here, and best-of-three sets forgives a lot. Claude Sonnet was highest at 5.6%; DeepSeek was lowest at 2.5%.
Daniel Merida (3.5¢, 2.4% blend). The only unseeded man left, ranked No. 59, and the only one who is here because somebody else pulled out: he entered the draw as the replacement for Ethan Quinn. He is the only man in the last eight who had to play a first-round match, and he has won four in a row since: the wildcard Draxl, then Ugo Humbert, Alex Michelsen and Tallon Griekspoor. He is the only one of these three dark horses the panel rates BELOW the market, and the seats disagreed sharply about how far: Claude Fable and Kimi held him at 3.0% while DeepSeek priced him at 0.8%.
Where The Panel Changed Its Mind
Every seat read the other six anonymized boards before setting its final number. Three of the results are worth reading.
I revised modestly: nudged Shelton up toward the group after A, C and G stressed that a set-less defending champion on hard deserves more than my raw bracket math gave, and lifted Nakashima after F correctly flagged that his Darderi quarterfinal plus a Jodar/Fils semifinal is the most valuable path on the board. — Kimi
[Editor's note: the Shelton revision is as described, from 23.9% to 25.5%. The Nakashima move went the other way, from 12.3% down to 10.5%, so this seat argued itself toward a player it then priced lower.]
Claude Sonnet went the opposite direction on the favorite, cutting Shelton from 31.8% to 29.3% and putting the weight into the tail.
BASE RATES: this title has gone to non-elite champions repeatedly (2022, 2024), and best-of-three narrows favorite-underdog gaps, so I kept a real tail on Jodar/Nakashima/Darderi/Mérida rather than crowning Shelton near 33%. — Claude Sonnet
That is a checkable claim, and the ledger supports it. Pablo Carreno Busta won this title in 2022 and Alexei Popyrin won it in 2024, neither from anything resembling a favorite's position. Sonnet acted on it, lifting Darderi from 3.3% to 5.6% and Merida from 0.5% to 2.3%.
One seat held its outlier and said why.
I held my numbers close to an independent path-probability model, which gives Shelton a higher title chance (34.4%) than most forecasters because I rate his final win probability against any bottom-half opponent at ~75%, higher than the 65–70% implied by others. — DeepSeek
DeepSeek carried the highest Shelton number in both rounds, 33.0% and then 34.3% once its board is normalized to 100. Its argument is not really about the quarterfinal, which it puts at 63/37. It is about the final: if the bottom half of the draw sends up a player who has never won a Masters 1000, Shelton's edge in that last match is larger than the rest of the panel assumes.
What Would Change The Panel's Mind
Four things, all checkable within days, with the direction each pushes the board.
- The Shelton-Mensik quarterfinal. This is the hinge every seat named. Shelton through and his 28.3% concentrates sharply; Mensik through and he becomes the panel's favorite, not its second choice at 15.4%.
- Any fitness news on Shelton before he plays. All seven seats independently named an injury or fatigue report on Shelton as the single item that would move their board most, which is the rarest kind of agreement this panel produces. He has played three matches without dropping a set, so there is no on-court evidence either way, and that is exactly why a report would matter.
- The Jodar-Fils quarterfinal. The market has 38.5 cents riding on a match that eliminates one of them. If Jodar wins, the panel's 13.0% was the low read on a player heading for a Masters semifinal at 19. If Fils wins, the market's 22 cents on Jodar was the mistake.
- Darderi beating Nakashima. Every seat discounted him because all seven of his tour-level finals came on clay. A hard-court Masters semifinal would be direct evidence against the one adjustment the whole panel agreed on.
Settlement Timeline
| What | When |
|---|---|
| Round Of 16 Completed | Sunday, August 9, 2026 |
| Quarterfinals | From Monday, August 10, 2026 |
| Tournament Ends | Thursday, August 13, 2026 |
| Contracts Close And Expire | As soon as a champion is declared |
| Listed Expiration Stamp (Placeholder) | August 30, 2026 |
This page is re-scored when the story moves. Prices as of August 9, 2026.
The Bottom Line
The 2026 National Bank Open lost Jannik Sinner, Carlos Alcaraz and Novak Djokovic before a ball was struck, then lost 25 of its 32 seeds: 24 beaten on court and Felix Auger-Aliassime to a back injury before his opening match. Alexander Zverev, Daniil Medvedev and Taylor Fritz all went out in the second round. What is left is a quarterfinal field in which six of the eight men have never won a Masters 1000 event.
The market has responded by pricing two of them within half a cent of each other, at 22.5 and 22 cents. The panel says those two are not close. Shelton sits at 28.3% because he has won this exact tournament, and because the one serious obstacle in front of him is a quarterfinal rather than a whole half of the draw. Jodar sits at 13.0% because three brilliant matches, two of them against top-13 seeds, do not outweigh a thin hard-court resume: one career title, won on clay, and an 0-1 record in hard-court finals.
One of those reads is wrong, and this tournament will say which within the week. That is the useful thing about a board that settles in days rather than months: the grade arrives almost immediately, and it goes on the public scoreboard either way.
