The World Cup is about to kick off. On opening day, two things happen almost simultaneously.
One is money. As of pre-match, the combined trading volume for the "World Cup Champion" contracts on the Kalshi and Polymarket platforms has exceeded $20 billion—and not a single match has been played yet [1]. The other is legitimacy. Two days before the opening match, crypto exchange Kraken was announced by FIFA as the World Cup's Official Crypto Exchange Supporter (Supporter level, covering North America and Europe; financial terms undisclosed) [5][6][7].
But the real question this article asks is a more fundamental one that sports media won't touch: When the World Cup actually kicks off, how exactly do these on-chain contracts "know" who wins? How do prices move with the match, how are contracts handled when a team is eliminated, who decides the outcome, and how much of those tens of billions staked is real—this is the first day prediction markets move from "pre-match static numbers" into the "operation of the tournament."
Continuing from the previous issue (the pre-match panorama of static data), this issue covers: how this machine truly operates at this very moment of kickoff.
Data as of June 11, 2026. All prices and trading volumes are subject to change and may differ at time of publication. This article does not predict any match outcomes.
Act One · How the $20B Was Stacked—And "Which $20B"
Let's break down that eye-catching number first.
By pre-match, the cumulative trading volume for the "World Cup Champion" contract on Polymarket alone reached about $1.9 billion (since its launch on July 2, 2025) [4]; Kalshi contributed another approximately $132 million with its counterpart contract; combined, they first surpassed $20 billion on June 8 (two days before kickoff) [1]. If we expand the view to all platforms and all World Cup-related contracts (not just the "champion" one), the sector's total trading volume has exceeded $30 billion [3].
Connecting back to the last issue: on June 5, we recorded $1.6 billion for Polymarket alone. Six days later, the same metric reached $1.9 billion. Measured with the same ruler, the curve is continuous.
Looking at the entire sector, Pew Research Center data shows: the combined monthly trading volume of Kalshi and Polymarket grew from less than $5 billion in September 2025 to about $24 billion in April 2026; for comparison, the monthly average betting volume for legal U.S. sports gambling last year was about $14 billion. The scale of prediction markets has now surpassed that of traditional sports betting [3].
As for what the market currently thinks about the champion—as of June 10, Spain is priced around 16.5% on Polymarket and 17.4% on Kalshi, France follows closely around 16%, England and Portugal each around 11%, defending champion Argentina around 9%, and Brazil around 8% [1]. These are just the market's current pricing, not predictions, and certainly not this article's judgment.
Act Two · Per-Match Contracts: How the Machine Operates After Kickoff
The $20 billion is for that one long-term "who wins the championship" contract. But what truly comes to life daily after the tournament starts are the per-match contracts covering each game.
The odds for opening day matches are already posted (the following are current market prices, serving only as on-the-spot snapshots, not constituting any prediction): In the win-draw-lose contracts for the opening match, host nation Mexico is priced as the heaviest favorite; the day's other match, South Korea vs. Czech Republic, is seen by the market as the most evenly contested of the four openers, with South Korea around 37 cents, Czech Republic around 34 cents, and a draw around 32 cents—almost a three-way split; while USA vs. Paraguay is seen as a "coin flip"—USA around 50 cents, Paraguay around 23 cents, draw around 29 cents. The "total goals" contracts for all four opening matches lean toward low scores, with the implied probability for "under 2.5 goals" between 57% and 59% [2][8].
The operating logic for each contract is the same: the price floats between 1 cent and 99 cents, directly read as an implied probability—50 cents means the market assigns about a 50% probability. As the match progresses and the score changes, the price fluctuates accordingly.
And here is a mechanism that will repeatedly occur after kickoff but is rarely explained: elimination zeroing. When a team becomes mathematically impossible to win the championship, its "Champion Yes" contract will immediately zero out and settle as "No" [4]. As the group stage progresses into its later rounds, the first batch of eliminated teams will appear—that will be one of the first large-scale, real-world moments of on-chain contracts zeroing out. It's one of the most critical on-chain moments to watch during the tournament.
Act Three · How On-Chain Contracts "Know" Who Wins: Two Paradigms
This is the one thing most in need of explanation on opening day, yet almost no one explains it.
An on-chain contract is, in itself, just a piece of code. It doesn't watch the game. So, after Mexico and South Africa finish playing, how does that "Mexico Wins" contract on-chain "know" what actually happened in the real world and then pay the people who guessed correctly?
The answer is called an oracle—the bridge that feeds real-world information to on-chain contracts. And currently, the industry has two different paradigms answering this question.
The First: UMA's "Optimistic Oracle," used primarily by Polymarket (accounting for about 78% of its markets). "Optimistic" means: first assume someone's submitted result is correct, then leave a period for others to challenge. The specific process is—a proposer on a whitelist, staking a $750 PUSD bond, submits the result "Mexico wins"; next, there is a 2-hour challenge window where anyone can stake an equal bond to oppose; if no one challenges, the market automatically settles based on this result, with each correct contract instantly receiving $1 and incorrect ones zeroing out, with no need for manual claiming. If someone challenges, the dispute escalates to a vote by UMA token holders for resolution [9].
This whitelist has a history: In March 2025, a market called "Ukraine Minerals" suffered a governance attack affecting approximately $7 million, exposing the structural weakness of "anyone can submit results." So in August, UMA passed the UMIP-189 proposal, restricting proposal rights to a whitelist—expanding from an initial 37 addresses to 177 by November 2025, with the threshold being at least 5 proposals and over 95% accuracy in the past 6 months. But it must be emphasized: challenge rights remain open to everyone—you don't need to be on the whitelist to oppose any result you believe is wrong [10].
The Second: Chainlink's "Multi-Source Aggregation," used by FIFA's official partners ADI Predictstreet and Myriad (Polymarket also uses Chainlink for about 15% of its markets). On June 9, ADI Predictstreet announced the adoption of Chainlink as its exclusive oracle infrastructure, actively aggregating match results from multiple data sources to automate market creation, settlement, and payment, touting "no disputes, second-level settlement" [11].
Placing the two paradigms side by side, the difference becomes clear: faced with the question of "who decides the truth," UMA's answer is "trust first, leave a challenge window, vote in case of dispute," while Chainlink's answer is "aggregate from multiple authoritative data sources, feed automatically, leave almost no room for dispute." This isn't an either-or situation—Polymarket primarily uses UMA but also integrates Chainlink for some markets; for events like World Cup results that are "clear and unambiguous," both paradigms are far safer than for ambiguous political or geopolitical markets.
ESPN will tell you who won. But how an on-chain contract "knows" who won—that's two entirely different designs of decentralization operating behind the scenes.
Act Four · Of Those Tens of Billions, How Much Is Real
This series has been discussing how prediction markets are growing. But as a piece of content that doesn't adopt a casino narrative, we must add a sobering counter-question to this "$20 billion" story.
First, look at how money settles. These contracts are all denominated in dollar-pegged stablecoins like USDC and settle on the Polygon chain [12]. One detail is telling: a contract that is almost certain to win often trades between $0.995 and $0.999 before official settlement—because some traders prefer to sell now at $0.999 to get their money rather than wait a few hours for the oracle process to complete and receive the full $1 [9]. This is the immediacy brought by the stablecoin settlement layer.
But next comes that sobering counter-question. The benefit of being on-chain is that everything is publicly viewable and auditable by anyone. But precisely because it's public, the issues are also visible: researchers at Columbia University estimated in a study that about 25% of Polymarket's historical trading volume might be "wash trading" (i.e., the same party buying and selling from itself to artificially inflate trading numbers) [13]; and for sports-related markets, this proportion was about 45% across all periods, even reaching 90% during one week in 2024 [14].
It must be emphasized that these are estimates from third-party research, not official platform data, and the methodology is also debated—for instance, a statistics professor at Rutgers University believes the narrative about manipulation is exaggerated and may even carry a certain bias. But even discounting the estimates, it still reminds us of one thing: when you see the number "$20 billion," it measures the scale of market activity, not $20 billion of genuine, hand-to-hand exchange from different people.
Platforms are also responding. Kalshi introduced new anti-insider trading rules on June 10—for markets deemed higher risk of manipulation, requiring traders to disclose employer information and introducing a market risk scoring system [15]. This is a hurdle prediction markets must overcome on their path to maturity.
Closing · The Same Bet, Two Identities
Finally, back to the most fundamental matter—what exactly are these contracts considered in your location.
Some put it bluntly: the same $100 bet on France to win the championship, on a sportsbook platform like DraftKings, is "gambling" regulated by individual states and strictly geofenced; while buying a "France Wins" contract on Kalshi is a "trade" legal for adults in all 50 U.S. states. The same bet, the same shout during a penalty shootout, but with vastly different legal identities [16].
This is precisely the core of the regulatory divergence covered in the previous issue of this series: prediction markets take the path of "event contracts" under the U.S. CFTC, while sports betting takes the path of state-by-state licensing. And in these opening days, states like Minnesota, New Mexico, and Nevada still contend that these so-called prediction markets are essentially "sports betting in disguise." The legal battle over "what it actually is" is far from over.
The same World Cup contract can have completely different legal statuses in different jurisdictions. Readers must verify the rules applicable to their own location.
The opening whistle blows, and this machine staked with tens of billions, denominated in stablecoins, adjudicated by oracles, and watched by regulators, begins its real operation. Over the next month, we'll see it settle for real for the first time, zero out for real for the first time, and after the final on July 20th, look back to see who got it right—the market or those supercomputer models.
How it operates might be more worth watching than who ultimately lifts the trophy.
