August 24, 2026 · 10 min read · by Jake Hari
On Saturday the USTA handed Serena Williams and Carlos Alcaraz a wild card into the US Open mixed doubles, and by Sunday every outlet in sports had the story: the 23-time Grand Slam champion back at Flushing Meadows for the first time since 2022, next to the defending US Open men's champion, opening Tuesday with the $1 million settled Wednesday night. What nobody had, anywhere, was a price. I spent Sunday night looking for one. This piece is what I found, and what I didn't.
The Quick Answer
You cannot trade US Open mixed doubles on Kalshi as of August 24; the exchange lists no market on the event, and no major US sportsbook had posted a public winner board we could quote by Monday morning either. The closest live number attached to this event is Carlos Alcaraz in the low 30s in cents to win the men's singles title, and Tuesday's mixed doubles is the first public fitness evidence that could move it. The full market map, the live Kalshi tennis board, and how to read a 16-team sprint for $1 million are below.
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The Wild Card That Sold Out Fan Week
Start with what actually got announced, because the tennis is remarkable even before you try to bet on it. Williams has not played the US Open since her 2022 farewell. She came back to tennis this summer, lost in the first round of Wimbledon singles and picked up a knee injury doing it, then played doubles with Venus at the Cincinnati Open. She is not entering the singles in New York; the USTA gave its remaining women's wild card to Sofia Kenin. Mixed doubles, with the men's title favorite carrying the other half of the court, is the comeback vehicle.
Alcaraz's half of the story matters more for anyone holding a position. The world No. 2 has not played a competitive singles match since the Barcelona Open in April, when a right wrist injury shut his season down. This event is his first live tennis since, two days of it, before the singles draw comes out Thursday and the singles main draw starts Sunday, August 30.
The event itself was rebuilt last year into something the sport's biggest names actually show up for: 16 teams, two days, Arthur Ashe and Louis Armstrong, during Fan Week before the singles begin. The 2025 edition drew 78,000 spectators and sold out Ashe both nights, and the winning team splits $1 million, part of the total player compensation the USTA pushed to $108 million this year. The field around Williams and Alcaraz is absurd by mixed doubles standards. Aryna Sabalenka, the defending US Open women's singles champion, is playing with Novak Djokovic and his 24 majors. Jessica Pegula pairs with Taylor Fritz, Taylor Townsend with Alexander Zverev, and Sara Errani and Andrea Vavassori arrive as two-time defending champions of this event. Per the schedule, Williams and Alcaraz open Tuesday against a team that comes through Monday's qualifying.
So the most famous team of the tennis year plays tomorrow, for a seven-figure prize, in a stadium that sold out both nights last year. Now try to put a number on them.
Where You Can Actually Bet US Open Mixed Doubles
The honest map, as of Monday morning, August 24, has three territories.
Sportsbooks own this market when it exists. A mixed doubles tournament winner market is a real sportsbook product; the event was priced by books last year, and the aggregator Oddschecker maintains a Mixed Doubles US Open winner page. When we pulled that page and swept the public tennis menus early Monday morning, though, no full 16-team board a US bettor could act on had surfaced anywhere we could quote, and no outlet had published prices either. That should change fast now that the field and draw are set. When boards do post, expect them to be short menus with wide margins built in, the standard treatment for a novelty tennis market, which makes shopping more than one book the whole game. Our free expert picks board is where our tennis and futures reads land when our experts take a side on events like this one.
Kalshi does not list the event. I went through the exchange's catalog directly rather than trusting the app's search bar. Kalshi has two mixed doubles series registered in its catalog, KXMIXEDDOUBLES and KXMIXEDDOUBLESMATCH, so the plumbing for this event class exists, but on a direct catalog pull early Monday morning both showed zero open events, and there is no tournament winner market. If your plan was to buy Williams and Alcaraz at some price on a regulated exchange, there is nothing to buy. Worth remembering here: Kalshi contracts are CFTC-regulated event contracts rather than sports bets in the legal sense, availability varies by state, and the platform's own eligibility check is the place to confirm access.
What Kalshi does list is singles, in size. The men's and women's winner boards are the two live US Open tennis markets on the exchange, and the men's board alone has traded about 6.6 million contracts across its 34 player markets. Which brings us to the number that actually matters this week, because the three biggest names on that board are all playing mixed doubles first.
What Kalshi's Live Tennis Boards Say
Here is the top of the men's singles winner board as I pulled it Monday morning, August 24. Prices are cents per contract that pays $1 if that player wins the title.
| Player | Last Trade | Bid | Ask |
|---|---|---|---|
| Carlos Alcaraz | 33¢ | 32¢ | 33¢ |
| Alexander Zverev | 20¢ | 19¢ | 20¢ |
| Novak Djokovic | 10¢ | 9¢ | 10¢ |
| Ben Shelton | 8¢ | 7¢ | 8¢ |
| Arthur Fils | 7¢ | 6¢ | 7¢ |
| Rafael Jodar | 5¢ | 4¢ | 5¢ |
| Taylor Fritz | 5¢ | 4¢ | 5¢ |
The full board runs 34 names; this is its liquid top.
The row worth sitting with is the top one. A price in the low 30s makes Alcaraz the clear favorite for a Grand Slam he has not prepared for with a single competitive singles match, and it is a real quote, with a one-cent spread and heavy interest behind it: his contract has traded roughly 745,000 contracts lifetime with about 491,000 still open. The market closed him at 34 cents yesterday and opened this week at 33, a drift inside the spread that says little by itself; the real repricing window opens Tuesday. He is the favorite mostly because Jannik Sinner's withdrawal with a knee injury removed the world No. 1 from the field entirely, and the crowd had to put that probability somewhere. One settlement note for anyone new to these contracts: a winning contract pays its dollar after the men's final in mid September, while a withdrawal resolves that player's contract to zero immediately, which is exactly what happened to Sinner holders last week.
The women's board tells the same story from the other side of the net. Sabalenka leads it in the low 20s, with Swiatek and Coco Gauff behind her. Stack the two boards against the mixed doubles entry list and the situation gets a little funny: Sabalenka and Djokovic, a pairing holding just over 30 cents of combined singles equity, will be playing short-set tennis on the same courts as Williams and Alcaraz, and Alexander Zverev, the 20-cent second choice, is out there too with Taylor Townsend. If you want the deeper comparison of how the exchanges and traditional books price this same singles field against each other, we broke that down in our US Open odds comparison, and the daily movers across every Kalshi board land on our Kalshi picks page.
The 33-Cent Question: What Tuesday Actually Prices
Here is the payoff I promised in the opening, and the reason the missing mixed doubles market matters less than it looks. To the betting world, Tuesday doubles as the first public fitness test of the men's singles favorite, the only one anyone gets before the tournament starts.
Alcaraz has not hit a ball in competition since April. That wrist drives his entire game; his forehand is the shot that broke down Casper Ruud's backhand wing when he won the first of his two titles here in 2022, a pattern we pointed at on our US Open final show that week, too much pace into a side that could redirect but never punish. A 33-cent favorite whose weapon is the injured joint, showing it in public for the first time, on a hard court, on television. That information never needed a mixed doubles market to be tradeable. The singles board is sitting right there with a penny-wide spread.
When we had eight AI models price the full men's board with the market hidden, the mixed doubles event kept surfacing as the single biggest unresolved variable on Alcaraz's number, and the panel's own read was blunt: all eight seats priced him below the market, with a median of 16.4% against the 33-cent quote, the widest gap on the board. In plain terms, our models already think 33 cents is expensive, and a clean wrist on Tuesday is the one piece of evidence that could close that argument in the market's favor. The mechanism cuts both ways. If he moves freely and rips through two days of short sets next to Williams, the low-30s price starts looking conservative for a two-time champion in a field with no Sinner in it. If he looks compromised, or scratches, the probability has to travel, and the board above tells you where it goes: Zverev at 20 cents, Djokovic at 10 and Shelton behind them are where the market would push that probability next. Either way, re-run the arithmetic at whatever price you are actually offered when the matches end Wednesday, because these quotes will not sit still through a televised fitness reveal.
There is one more wrinkle the format adds. Short sets flatter a player protecting an injury. Through the semifinals the matches are best-of-three to four games with no-ad scoring and a 10-point tiebreak in place of a third set, about the least physically demanding shape professional tennis offers, one a team can win in well under an hour; only Wednesday's final stretches to six-game sets and puts anything like real load on the wrist. A clean Tuesday tells you the joint survives contact, and much less about whether it survives a five-set match on Labor Day weekend. Treat the mixed doubles as a screen, the kind that can rule a player out but can only partially rule him in.
How To Price A 16-Team Sprint When The Boards Post
Whenever the sportsbook boards do go up this week, the temptation will be to read them like a singles field: best players, shortest prices. Resist that, for two structural reasons the format facts above already set up.
First, that same no-ad, short-set format that protects Alcaraz's wrist also compresses the talent gap. Fewer games means fewer chances for the better team to grind out its edge, and every no-ad deuce point settles in one swing what a full advantage battle used to decide. In a field this deep, a seven-figure incentive and a two-day sprint push every price toward the middle. Favorites in this event should be priced weaker than their names suggest, and the one edition of this format on the books backs the specialists: Sara Errani and Andrea Vavassori, career doubles players, won the revamped 2025 event over a field stacked with singles stars, beating Iga Swiatek and Casper Ruud in the final, a year after taking the title in the old format. Doubles craft, returning and net play and communication, is a real edge that a marquee-name board hides.
Second, apply that lens to the team everyone will bet with their heart. Williams is 44, her comeback summer so far amounts to a first-round Wimbledon singles exit and doubles with Venus in Cincinnati, and she is managing the knee she hurt at Wimbledon; Alcaraz brings the best half of any team in the draw and a four-month layoff. The romantic outcome pays $1 million and would be one of the great sports stories of the year. The sober read is that the pairing profiles as a mid-tier team in a stacked 16, well behind the specialists and the healthy top seeds on paper, and any early price that treats them as a favorite on fame is a price to shop against rather than take. If you want the wager anyway, as a souvenir with upside, size it like one.
What To Watch From Here
The window on all of this is short, which is the point of getting the map straight today. Qualifying is Monday, Williams and Alcaraz open Tuesday, the final is Wednesday night, the singles draw lands Thursday, and the singles main draw starts Sunday. If a sportsbook mixed doubles board posts in that window, treat it as a small, fast-moving novelty market and shop it across books before taking anything.
The sharper use of Tuesday is to watch Alcaraz the way the singles market will. Serve speed is the cleanest public tell on a wrist, so watch whether he is landing first serves at his usual pace or guiding them in. Watch whether the forehand comes through the ball or steers it, and whether he takes his cuts on returns or blocks them back. And keep an eye on Zverev's court too, for a different reason: the 20-cent second choice is the nearest market alternative if Alcaraz looks compromised, and he is on the same grounds all week. By Thursday night, any mixed doubles price that finally posts will matter less than how the singles market repriced Alcaraz after two televised appearances; whatever Tuesday reveals will have been absorbed into the boards where the real liquidity lives. The missing mixed doubles market was never the instrument that mattered most this week. The 33 cents was.
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FAQ
Can you trade US Open mixed doubles on Kalshi?
Not as of August 24, 2026. Kalshi carries mixed doubles match series in its catalog, but no US Open mixed doubles event is open, and there is no tournament winner market. The live US Open tennis markets on Kalshi are the men's and women's singles winner boards.
When do Serena Williams and Carlos Alcaraz play their first mixed doubles match?
The 16-team main draw runs Tuesday, August 25 and Wednesday, August 26, 2026 at Arthur Ashe and Louis Armstrong Stadiums, and Williams and Alcaraz open against a team that comes through Monday's qualifying event. The winning pair splits $1 million.
Hero illustration: OddsShopper, in the house collage style. Serena Williams photo by Katherine Shann, licensed CC BY-SA 2.0; Carlos Alcaraz photo by Barcex, licensed CC BY-SA 4.0; photos cropped, toned, and composited.
