Crypto rails made prediction markets global, gambling laws may make them local again

South Korean police opened the country’s first illegal gambling probe into domestic Polymarket users on Jun. 5, targeting residents who placed bets on the Jun. 3 local election outcomes.

The Gangwon Provincial Police Agency is leading the investigation at the request of the National Police Agency, tracing cryptocurrency transaction records to identify users nationwide.

Those identified face potential fines of up to 10 million won ($6,500) under Article 246 of the Criminal Act. Polymarket’s resolved 2026 Seoul mayoral election market alone showed a total volume of $52.2 million, putting activity well into the tens of billions of won across Korean election markets.

South Korea ranks 15th in Chainalysis’ 2025 Global Crypto Adoption Index, the latest addition to a list that already includes India (#1), Brazil (#5), Indonesia (#7), and Thailand (#17).

Six of the top 20 crypto adoption markets have now moved against prediction platforms through gambling law, derivatives restrictions, ISP blocks, user enforcement, or some combination of all four.

Crypto adoption and legal permission for crypto-native financial products diverged, and prediction markets are caught in that gap.

The volume that drew attention

Combined monthly trading volume on Kalshi and Polymarket climbed from under $5 billion in September 2025 to over $10 billion in May 2026.

For context, legal US sportsbooks averaged about $14 billion in monthly wagers throughout 2025. Sports, politics, and crypto drove 91% of Kalshi’s global volume and 90% of Polymarket’s since July 2024.

Sports alone accounted for 80% of Kalshi volume, while politics accounted for 32% of Polymarket’s, and those product concentrations are precisely where regulators draw the hardest lines.

Since the start of 2026, Kalshi flagged over 400 suspicious trades, more than double its total for all of 2025. Platforms built market integrity mechanisms faster than legal frameworks emerged to govern them.

How the classification breaks down

On Apr. 24, Brazil’s Finance Minister Dario Durigan announced that the National Monetary Council’s Resolution No. 5,298 blocked 27 platforms, including Polymarket, Kalshi, PredictIt, and Robinhood’s forecasting feature. It also prohibited derivatives tied to sports, online gaming, political, electoral, cultural, and social outcomes.

Only contracts tied to economic benchmarks, such as exchange rates or interest rates, survived the cut. Durigan said the government wanted to prevent an unregulated betting market from embedding itself in household finances at a moment when Brazil was already working to reduce consumer debt.

Kalshi’s timing was particularly poor: the platform had announced a Brazilian distribution partnership with brokerage XP International in March 2026, one month before the block took effect.

India treated the same product through a different legal pipe and arrived at the same outcome. Both houses of Parliament passed the Promotion and Regulation of Online Gaming Act 2025 in August 2025, received presidential assent the same month, and came into force on May 1, 2026.

Under the law, prediction markets fall into prohibited online money gaming, with the classification covering event contracts regardless of how operators frame them as derivatives or forecasting tools.

MeitY issued a blocking order against Polymarket and is preparing a similar order for Kalshi. On Apr. 25, the ministry sent a letter specifically to VPN providers, warning them against enabling access to blocked platforms.

Targeting VPN providers alongside platforms extends enforcement one layer deeper into the access stack.

Indonesia blocked Polymarket after markets on the potential early end of President Prabowo Subianto’s term circulated on the platform. Thai cybercrime authorities moved earlier to classify Polymarket as illegal online gambling.

Spain ordered ISPs to block Polymarket and Kalshi on May 26, pending disciplinary proceedings by the gambling watchdog, DGOJ, expected to last 3 to 4 months.

Spain sits outside Chainalysis’ top 20, but its enforcement rests on consumer-protection machinery, giving regulators a framework that applies regardless of whether the product is classified as a derivative.

The US version

The United States presents a jurisdiction fight, as federal CFTC regulation coexists with state-level gambling claims over the same contracts, and that tension remains unresolved.

Kalshi holds a designated contract market license, and Polymarket relaunched a US exchange in late 2025 after acquiring a regulated derivatives firm.

Several states argue that sports and election contracts cross into gambling territory regardless of CFTC oversight, resulting in litigation that carves up the domestic market into patches.

In April 2026, Polymarket International recorded $9 billion in trading volume, compared with $1.3 billion on Polymarket US.

The US House Oversight Committee opened a probe into Kalshi and Polymarket in May 2026 over whether government employees were trading on classified information, with Chair James Comer signaling potential legislation to bar members of Congress and administration officials from participating.

That market-integrity argument adds legislative pressure independent of the CFTC-versus-state question.

How far the collateral wedge travels

In the bull case, regulators in key financial centers accept event contracts as legitimate derivatives when used for economic, financial, or hedging purposes, and require platforms to strip out sports, politics, and elections to operate legally.

Kalshi’s CFTC-regulated model serves as the template, with platforms bifurcating into a compliant financial-contract layer and a separate offshore, crypto-native layer.

The offshore layer continues to attract retail demand until payment friction, app-store enforcement, or VPN crackdowns gradually narrow access.

In the bear case, Brazil’s category-wide derivatives ban and India’s online money-gaming classification spread to additional top crypto-adoption markets.

Sports, politics, and elections are the products users actually want, and those are precisely the contracts regulators target. Platforms that depend on those categories for 90% of volume cannot strip them out without becoming structurally different businesses.

A market-integrity incident, such as a documented case of insider trading on a geopolitical event or election, accelerates the cascade. Kalshi flagged 400-plus suspicious trades in the first five months of 2026 alone. The raw material for a triggering event already exists.

Regulated financial contracts will serve jurisdictions willing to treat narrow categories of events as CFTC-style derivatives. Licensed gambling products will be offered on platforms that classify outcome contracts as bets and comply with local consumer protection regimes.

Geofenced crypto-native markets will continue to reach users through stablecoins, wallets, and VPNs until access, payment processing, or enforcement pressure catches up.

South Korea’s probe shows the enforcement logic is moving from platform blocking to user liability, with authorities tracing crypto transaction records to identify individuals and summon them for questioning.