Worst bets, all time.
The 100 largest paper losses we've recorded across Polymarket and Kalshi. Big size, bad call. The cost of doing business at scale, or the price of arrogance, depending on the trade.
These are backtest data
How backtesting worksResolved trades are what a strategy gets scored on.
Every trade on this page has a known outcome, which is what makes it possible to measure a rule instead of guessing at one. Write a rule over trades like these and Rivo scores it: our longshot rule went 105 wins and 345 losses and still returned +67.5% at $100 a trade.
Ranked
Numbers 2 through 100
#2-$584.5K
LOS ANGELES DODGERS
Colorado Rockies vs. Los Angeles Dodgersstake $584.5K·@ 84¢Jul 8, 2026#3-$555.7K
YES
Will Argentina win the 2026 FIFA World Cup?stake $555.7K·@ 10¢Jun 16, 2026#4-$510.0K
FELIX AUGER-ALIASSIME
Roland Garros ATP: Felix Auger-Aliassime vs Flavio Cobollistake $510.0K·@ 51¢Jun 3, 2026#5-$489.5K
TEAM SPIRIT
Dota 2: Team Spirit vs TEAM VISION - Game 1 Winnerstake $489.5K·@ 49¢Aug 21, 2026#6-$455.7K
NO
Will Morocco win on 2026-07-04?stake $455.7K·@ 47¢Jul 4, 2026#7-$447.5K
YES
Will IR Iran win on 2026-06-15?stake $447.5K·@ 54¢Jun 16, 2026#8-$412.9K
ARSENAL FC
Spread: Arsenal FC (-2.5)stake $412.9K·@ 51¢May 18, 2026#9-$400.2K
YES
Will Germany win on 2026-06-25?stake $400.2K·@ 66¢Jun 25, 2026#10-$368K
NO
Will Brazil win on 2026-06-29?stake $368K·@ 46¢Jun 29, 2026#11-$367.8K
YES
Will Argentina win the 2026 FIFA World Cup?stake $367.8K·@ 42¢Jul 15, 2026#12-$350.8K
YES
Will Manchester City FC win on 2026-05-19?stake $350.8K·@ 61¢May 19, 2026#13-$336K
FURIA
Counter-Strike: FURIA vs FUT Esports (BO3) - Esports World Cup Playoffsstake $336K·@ 56¢Aug 22, 2026#14-$330.2K
JESSICA PEGULA
Wimbledon WTA: Jessica Pegula vs Coco Gauffstake $330.2K·@ 79¢Jul 7, 2026#15-$330.1K
YES
Will Juventus FC win on 2026-05-24?stake $330.1K·@ 68¢May 24, 2026#16-$325K
TEAM FALCONS
Dota 2: Team Falcons vs Team Liquid (BO5) - 1win Essence Playoffsstake $325K·@ 65¢Aug 5, 2026#17-$314.2K
YES
Will Liverpool FC win on 2026-08-23?stake $314.2K·@ 51¢Aug 23, 2026#18-$314.2K
YES
Will Liverpool FC win on 2026-08-23?stake $314.2K·@ 51¢Aug 23, 2026#19-$306K
HURRICANES
Hurricanes vs. Golden Knightsstake $306K·@ 51¢Jun 6, 2026#20-$303.1K
YES
Will Türkiye win on 2026-06-14?stake $303.1K·@ 57¢Jun 14, 2026#21-$302.5K
NO
US x Iran permanent peace deal by June 15, 2026?stake $302.5K·@ 86¢Jun 13, 2026#22-$300.8K
MEXICO
Mexico vs. England: Team to Advancestake $300.8K·@ 47¢Jul 5, 2026#23-$300.3K
NIGMA GALAXY
Dota 2: Team Yandex vs Nigma Galaxy (BO3) - The International Playoffsstake $300.3K·@ 43¢Aug 21, 2026#24-$300.0K
HAITI
Spread: Morocco (-1.5)stake $300.0K·@ 51¢Jun 24, 2026#25-$298.9K
YES
Will Argentina win on 2026-07-03?stake $298.9K·@ 86¢Jul 3, 2026#26-$296.7K
YES
Will Belgium win on 2026-06-15?stake $296.7K·@ 62¢Jun 15, 2026#27-$295.6K
ARSENAL FC
Spread: Arsenal FC (-2.5)stake $295.6K·@ 52¢May 18, 2026#28-$295.2K
NO
US x Iran permanent peace deal by June 15, 2026?stake $295.2K·@ 88¢Jun 5, 2026#29-$293.7K
LOS ANGELES DODGERS
Colorado Rockies vs. Los Angeles Dodgersstake $293.7K·@ 84¢Jul 8, 2026#30-$293.7K
LOS ANGELES DODGERS
Colorado Rockies vs. Los Angeles Dodgersstake $293.7K·@ 84¢Jul 8, 2026#31-$291.6K
NO
US x Iran permanent peace deal by June 15, 2026?stake $291.6K·@ 87¢Jun 2, 2026#32-$290.3K
SPURS
Spread: Spurs (-5.5)stake $290.3K·@ 48¢Jun 4, 2026#33-$290.3K
SPURS
Spread: Spurs (-5.5)stake $290.3K·@ 48¢Jun 4, 2026#34-$289.3K
TOMMY PAUL
Cincinnati Open: Tommy Paul vs Flavio Cobollistake $289.3K·@ 51¢Aug 20, 2026#35-$289.3K
YES
Will Chelsea FC win on 2026-05-04?stake $289.3K·@ 66¢May 4, 2026#36-$287.2K
OVER
France vs. Morocco: O/U 2.5stake $287.2K·@ 51¢Jul 9, 2026#37-$286.8K
BOOMBOYS
Dota 2: BoomBoys vs Team Spirit (BO3) - The International Playoffsstake $286.8K·@ 32¢Aug 22, 2026#38-$284.1K
YES
Will Arsenal win the 2025–26 Champions League?stake $284.1K·@ 42¢May 29, 2026#39-$281.4K
FURIA
Counter-Strike: FURIA vs FUT Esports (BO3) - Esports World Cup Playoffsstake $281.4K·@ 55¢Aug 22, 2026#40-$280.6K
CONOR MCGREGOR
UFC 329: Max Holloway vs. Conor McGregor (Welterweight, Main Card)stake $280.6K·@ 28¢Jul 12, 2026#41-$274.5K
TIMBERWOLVES
Spurs vs. Timberwolvesstake $274.5K·@ 35¢May 13, 2026#42-$274.5K
YES
Will Manchester City FC win on 2026-05-19?stake $274.5K·@ 61¢May 19, 2026#43-$266.5K
TEAM VISION
Dota 2: TEAM VISION vs Team Spirit (BO5) - The International Playoffsstake $266.5K·@ 56¢Aug 23, 2026#44-$266.5K
TEAM VISION
Dota 2: TEAM VISION vs Team Spirit (BO5) - The International Playoffsstake $266.5K·@ 56¢Aug 23, 2026#45-$265K
NO
Will Brentford FC win on 2026-08-22?stake $265K·@ 53¢Aug 22, 2026#46-$262.3K
YES
Will United States vs. Paraguay end in a draw?stake $262.3K·@ 31¢Jun 13, 2026#47-$261.4K
TEAM VISION
Dota 2: TEAM VISION vs Team Spirit (BO5) - The International Playoffsstake $261.4K·@ 56¢Aug 23, 2026#48-$260K
YES
Will France win on 2026-07-18?stake $260K·@ 52¢Jul 18, 2026#49-$259.6K
YES
Will Belgium win on 2026-06-21?stake $259.6K·@ 62¢Jun 21, 2026#50-$255.0K
NO
Will Scotland win on 2026-06-13?stake $255.0K·@ 36¢Jun 13, 2026#51-$250.0K
YES
Will Belgium win on 2026-06-15?stake $250.0K·@ 66¢Jun 15, 2026#52-$249.8K
YES
Will Belgium win on 2026-06-15?stake $249.8K·@ 66¢Jun 15, 2026#53-$244.4K
YES
Will Arsenal win the 2025–26 Champions League?stake $244.4K·@ 44¢May 30, 2026#54-$243.1K
YES
Will Juventus FC win on 2026-05-17?stake $243.1K·@ 75¢May 17, 2026#55-$241.3K
NO
Will Chelsea FC win on 2026-08-24?stake $241.3K·@ 49¢Aug 24, 2026#56-$240K
YES
Will Arsenal win the 2025–26 Champions League?stake $240K·@ 48¢May 30, 2026#57-$240K
YES
Will Argentina win the 2026 FIFA World Cup?stake $240K·@ 42¢Jul 15, 2026#58-$238.3K
OVER
France vs. Morocco: O/U 2.5stake $238.3K·@ 51¢Jul 9, 2026#59-$238.3K
NO
Will Scotland win on 2026-06-13?stake $238.3K·@ 39¢Jun 14, 2026#60-$236.3K
SPURS
Spurs vs. Knicksstake $236.3K·@ 46¢Jun 11, 2026#61-$236.0K
ARGENTINA
Spain vs. Argentina: Team to Advancestake $236.0K·@ 41¢Jul 19, 2026#62-$236.0K
ARGENTINA
Spain vs. Argentina: Team to Advancestake $236.0K·@ 41¢Jul 19, 2026#63-$235K
YES
Will Türkiye win on 2026-06-19?stake $235K·@ 47¢Jun 20, 2026#64-$232K
SEATTLE MARINERS
San Diego Padres vs. Seattle Marinersstake $232K·@ 58¢May 17, 2026#65-$229.5K
CELTICS
76ers vs. Celticsstake $229.5K·@ 69¢May 2, 2026#66-$229.1K
TEAM FALCONS
Dota 2: Team Falcons vs Team Liquid (BO5) - 1win Essence Playoffsstake $229.1K·@ 60¢Aug 5, 2026#67-$229.0K
TEAM YANDEX
Dota 2: Team Yandex vs Team Spirit - Game 2 Winnerstake $229.0K·@ 42¢Aug 23, 2026#68-$229.0K
TEAM YANDEX
Dota 2: Team Yandex vs Team Spirit - Game 2 Winnerstake $229.0K·@ 42¢Aug 23, 2026#69-$228.2K
SPURS
Spurs vs. Thunderstake $228.2K·@ 42¢May 26, 2026#70-$228K
TEAM SPIRIT
Dota 2: Team Spirit vs TEAM VISION (BO3) - The International Playoffsstake $228K·@ 38¢Aug 21, 2026#71-$228.0K
TEAM VISION
Dota 2: TEAM VISION vs Team Yandex - Game 2 Winnerstake $228.0K·@ 57¢Aug 22, 2026#72-$228.0K
TEAM VISION
Dota 2: TEAM VISION vs Team Yandex - Game 2 Winnerstake $228.0K·@ 57¢Aug 22, 2026#73-$226.8K
SPURS
Spread: Thunder (-2.5)stake $226.8K·@ 45¢May 26, 2026#74-$225.3K
THUNDER
Spread: Thunder (-11.5)stake $225.3K·@ 48¢Apr 28, 2026#75-$220.7K
TEAM VISION
Dota 2: TEAM VISION vs Team Spirit (BO5) - The International Playoffsstake $220.7K·@ 56¢Aug 23, 2026#76-$220.5K
NO
Will Chelsea FC win on 2026-08-24?stake $220.5K·@ 49¢Aug 24, 2026#77-$220.1K
CAVALIERS
Knicks vs. Cavaliersstake $220.1K·@ 46¢May 25, 2026#78-$220K
OVER
Portugal vs. Spain: O/U 2.5stake $220K·@ 55¢Jul 6, 2026#79-$219.8K
TEAM YANDEX
Dota 2: Team Yandex vs Team Spirit - Game 2 Winnerstake $219.8K·@ 43¢Aug 23, 2026#80-$219.8K
TEAM YANDEX
Dota 2: Team Yandex vs Team Spirit - Game 2 Winnerstake $219.8K·@ 43¢Aug 23, 2026#81-$216.5K
YES
Will Rayo Vallecano de Madrid win on 2026-08-20?stake $216.5K·@ 40¢Aug 20, 2026#82-$215.9K
NO
US x Iran permanent peace deal by June 15, 2026?stake $215.9K·@ 87¢Jun 2, 2026#83-$212.4K
NIGMA GALAXY
Dota 2: Team Yandex vs Nigma Galaxy (BO3) - The International Playoffsstake $212.4K·@ 43¢Aug 21, 2026#84-$211.4K
CELTICS
76ers vs. Celticsstake $211.4K·@ 68¢May 2, 2026#85-$208.5K
FRANCE
France vs. England: Team to Winstake $208.5K·@ 66¢Jul 17, 2026#86-$206.4K
NO
Will Mexico win on 2026-06-30?stake $206.4K·@ 59¢Jul 1, 2026#87-$205.6K
YES
Will Germany win on 2026-06-25?stake $205.6K·@ 66¢Jun 25, 2026#88-$205.3K
YES
Will Vitality win IEM Cologne Major 2026?stake $205.3K·@ 82¢Jun 8, 2026#89-$200.0K
HAITI
Spread: Morocco (-1.5)stake $200.0K·@ 51¢Jun 24, 2026#90-$200.0K
YES
Will Netherlands win on 2026-06-14?stake $200.0K·@ 47¢Jun 14, 2026#91-$200K
THUNDER
Spurs vs. Thunderstake $200K·@ 57¢May 31, 2026#92-$200.0K
YES
Will Belgium win on 2026-06-15?stake $200.0K·@ 66¢Jun 15, 2026#93-$200.0K
YES
Will Belgium win on 2026-06-15?stake $200.0K·@ 66¢Jun 15, 2026#94-$200.0K
YES
Will Belgium win on 2026-06-15?stake $200.0K·@ 66¢Jun 15, 2026#95-$199.6K
HURRICANES
Golden Knights vs. Hurricanesstake $199.6K·@ 61¢Jun 2, 2026#96-$198K
YES
Will Paris Saint-Germain FC win on 2026-08-23?stake $198K·@ 66¢Aug 23, 2026#97-$198K
YES
Will Paris Saint-Germain FC win on 2026-08-23?stake $198K·@ 66¢Aug 23, 2026#98-$197.1K
NEW YORK YANKEES
New York Yankees vs. Baltimore Oriolesstake $197.1K·@ 60¢May 13, 2026#99-$196.8K
MAGDALENA FRECH
Roland Garros WTA: Jil Teichmann vs Magdalena Frechstake $196.8K·@ 62¢May 27, 2026#100-$194.5K
VLASTO CEPO
UFC Fight Night: Gilbert Urbina vs. Vlasto Cepo (Middleweight, Prelims)stake $194.5K·@ 73¢Aug 1, 2026