The Biggest Bets Ever Placed on Kalshi

Everything on this page comes with a source link, because the numbers are large enough that nobody should take our word for them. Kalshi's own tallies sometimes include combo markets that outside trackers leave out, so where two figures exist we give both. Dates are when the trade or the market happened.

1. The biggest single bet, $990,000 on Duke at 99 cents

On March 16, 2026 someone put $990,000 on top-seeded Duke to beat 16-seed Siena, buying at 99 cents. That is a bet to win roughly $10,000, which is the prediction-market version of picking up pennies in front of a steamroller, except the steamroller was Siena and it never arrived. InGame reports it as the largest single trade Kalshi has made public, per InGame, which also counted $2.34 billion traded over the first 4 days of that tournament and $645.7 million on day one.

2. The biggest parlay, $1 million on 3 legs, and it lost

NFL Week 1, September 2026. A taker staked $1 million on the yes side of a 3-leg parlay (Cowboys, Raiders, Eagles), part of 2 block trades totalling $3.7 million on the same ticket. The Giants beat the Cowboys and the whole thing went to zero, per InGame. The same weekend set Kalshi's all-time daily records, $2.426 billion on the Saturday and $2.433 billion on the Sunday, with parlays alone at about $1.47 billion a day.

3. The biggest market, the 2026 World Cup final at $1.27 billion

Two days before Spain played Argentina, Fortune put the final's winner contract at $1.27 billion, the single largest market in the platform's history. The whole tournament ran to $13.76 billion by DeFi Rate's API count and $22.42 billion by Kalshi's own figure, which includes combos. Mexico against England was the most-traded match at $401.9 million, and Kalshi says the tournament brought it 3 million new users.

4. The biggest longshot payout, $526 into $52,641 on the pope

On May 8, 2025 the conclave chose Robert Prevost, who had been trading at about 1 cent. CardPlayer reported a $526 position that paid $52,641, and Newsweek added a $274 ticket that paid $27,496, quoting Kalshi's Jack Such on the insanely large payouts from small trades. Kalshi's conclave volume was $6.7 million by CardPlayer's count. Longshots like this are the whole reason this site exists; the rest of them live in the Hall of Filth.

5. The biggest losing day, when takers dropped $70 million in 24 hours

July 11, 2026, the World Cup round of 16 with the United States and Mexico both playing. Takers lost more than $70 million on trades made that day, the biggest loss for takers of any day in Kalshi's history, on what was then a record $2.1 billion of volume and $17.2 million in fees, per InGame. Over the whole tournament takers lost $288 million before fees while Kalshi collected $430.4 million in fees. Bloomberg later put net retail losses on combo bets at $294 million for 2026 to date, as relayed by KuCoin News.

6. The biggest pure-sports market, the 2026 Masters at $460 million

Rory McIlroy's Masters win in April 2026 drew $460 million on the outright-champion market and $545 million across all Masters markets, the biggest sports event in the platform's history at the time, per Covers. It was overtaken within 3 months by the World Cup. Before either of those, the all-time single-market leader was the 2024 presidential winner contract at $535 million.

7. The biggest Super Bowl, $871 million on one Sunday

Super Bowl LX in February 2026 did $871 million on the day and more than $1 billion across all game-related markets, up about 2,700% on the year before, when the game market was $27 million, per Fortune. The Bad Bunny opening-song market alone cleared $100 million. Elsewhere in sport, Strickland against Chimaev at UFC 328 drew $52 million on one fight, with $11.1 million backing Chimaev, who lost a split decision, per DeFi Rate.

8. The biggest days and weeks

• Election night 2024: more than $1 billion traded, 1 million sign-ups, and a then-record $245 million day.
• December 21, 2025: $381.7 million, the record day at the end of a year in which Kalshi traded $23.8 billion, up 1,108% on 2024, per National Law Review.
• June 13 and 14, 2026: the first billion-dollar days ($1.224 billion and $1.236 billion) as lifetime volume crossed $100 billion, per DeFi Rate.
• September 12 and 13, 2026: $2.426 billion and $2.433 billion, the all-time daily records, inside a $12.98 billion week that was 92% of all Kalshi-plus-Polymarket volume, per SCCG Management.
• Year to date at the time of writing: $179.6 billion, with July 2026 the record month at $41.1 billion, per DeFi Rate's tracker.

What the biggest bets have in common

None of them are the weird ones. The $990,000 trade was a 99-cent favorite. The $1 million parlay was 3 NFL favorites. The record days are football Saturdays. The fun on Kalshi is at the other end of the price ladder, where $526 becomes $52,641 because a cardinal from Chicago got elected, and that is the end we cover on the daily board. The big money is boring; the small money is where the stories are.

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