Prediction markets have evolved from a niche crypto curiosity into a $21 billion-per-month asset class in under two years. Kalshi posted $31 billion in notional volume in June 2026 alone; Polymarket's Q1 2026 total reached $26.2 billion, up 90% quarter-over-quarter. Combined, the two platforms ac...
"We now have a circuit split on exactly that question, and the Supreme Court will have to intervene." — Rob Schwartz, Former CFTC General Counsel, Morgan Lewis & Bockius LLP
Prediction markets have evolved from a niche crypto curiosity into a $21 billion-per-month asset class in under two years. Kalshi posted $31 billion in notional volume in June 2026 alone; Polymarket's Q1 2026 total reached $26.2 billion, up 90% quarter-over-quarter. Combined, the two platforms account for roughly 85-90% of global prediction market activity.
The growth has attracted a regulatory response that now threatens to fragment the market along jurisdictional lines. A circuit split between the Third Circuit (April 2026, ruling that all event contracts are CFTC-regulated swaps) and the Ninth Circuit (August 28, 2026, ruling that sports event contracts are not swaps and states may regulate them as gambling) has made Supreme Court intervention near-certain. Meanwhile, 44 state attorneys general have asserted that the CFTC lacks authority over sports prediction markets, and multiple states have moved to block platforms outright.
The economic stakes are significant. Kalshi's valuation jumped from $11 billion to $22 billion in March 2026, and the company is targeting a $40 billion valuation in its next funding round, with an IPO planned for 2027. However, the sector faces structural integrity questions: insider trading probes, including a White House teleprompter operator fined $172,000 for trading on advance knowledge of presidential speeches, have exposed surveillance gaps that regulators are working to close.
The numbers establish the sector's trajectory. According to Pew Research Center data published in May 2026, combined monthly volume on Kalshi and Polymarket rose from under $5 billion in September 2025 to roughly $24 billion by April 2026. This represents approximately 380% growth in seven months.
Kalshi has dominated recent volume. The platform recorded $31 billion in total notional trading volume in June 2026, driven largely by FIFA World Cup activity, where prediction markets collectively exceeded $50 billion in volume, according to CoinDesk reporting. Sports contracts accounted for roughly 85% of Kalshi's June volume. In the week ending September 13, 2026, Kalshi processed $12.98 billion in weekly volume, up 60.9% from the week ending August 9. NFL Week 1 alone generated $983 million in direct NFL contracts.
Polymarket reached $10.57 billion in monthly volume in March 2026, crossing $10 billion for the first time. Its year-to-date total through September 13 stood at $55.61 billion. Polymarket's US arm, QCX LLC (operating as Polymarket US), grew from $1.3 billion in April to $1.8 billion in May, roughly 20% of the platform's global volume.
Together, Kalshi and Polymarket generated approximately $38-39 billion of the estimated $44 billion total notional volume recorded industry-wide during 2025, per TRM Labs analysis. Kalshi held a 92.1% share of regulated weekly contract volume as of mid-September 2026.
The legal architecture underpinning prediction markets fractured on August 28, 2026, when the Ninth Circuit ruled 3-0 against Kalshi in KalshiEX, LLC v. Assad. The court held that sports event contracts are not "swaps" under the Commodity Exchange Act (CEA) and that federal law does not preempt state gambling regulation.
The Ninth Circuit's reasoning was direct: "A contract on the outcome of a game, a point spread, a score, a player performance, or a multi-leg combo does not qualify as a swap under the statute merely because a platform calls it an event contract or lists it on a CFTC-registered exchange."
This contradicts the Third Circuit's April 2026 ruling, which held that all event contracts listed on CFTC-registered exchanges are swaps subject to exclusive federal jurisdiction. According to Bloomberg Law reporting, the circuit split creates what multiple legal analysts described as a near-certain path to Supreme Court review.
CFTC spokesman Zach Fulton responded that "the Commodity Exchange Act's grant of exclusive jurisdiction to the CFTC expressly preempts state regulation of swaps." Former CFTC Enforcement Director Aitan Goelman, now at Zuckerman Spaeder LLP, stated that "the court did a good job of explaining why the majority in the Third Circuit was wrong."
The practical impact is geographic fragmentation. Kalshi and Polymarket operate legally at the federal level in all 50 states under CFTC oversight. At the state level, however, Nevada has blocked major platforms, and Massachusetts, Michigan, and Washington have limited sports event contracts under court orders. Kentucky's Attorney General filed lawsuits against Kalshi, Polymarket, and their distribution partners alleging the platforms operate as unlicensed, illegal sports betting operations.
On June 10, 2026, the CFTC published a 267-page Notice of Proposed Rulemaking (NPRM) on public interest determinations for event contracts. The proposed rule replaces the prior approach of broadly prohibiting event contracts deemed "contrary to the public interest" with a structured three-step analytical framework.
The framework evaluates whether event contracts "involve" enumerated activities (unlawful activity, terrorism, assassination, war, or gaming), applies three general factors to assess public interest implications, and weighs those factors with no single factor being dispositive. The three factors center on price discovery utility, information aggregation benefit, and risk management function.
The comment period closed July 27, 2026. According to analysis by K&L Gates, the NPRM represents the CFTC's attempt to establish a workable regulatory framework rather than the blanket prohibitions that courts have found problematic. The rule, if finalized, would apply to all CFTC-registered Designated Contract Markets listing event contracts, including Kalshi and Polymarket's US operations.
Separately, the CFTC launched an internal review of "mention markets" in June 2026. These are contracts where traders speculate on whether specific words will appear in speeches, earnings calls, or broadcasts. Kalshi subsequently removed its sports-related mention exchanges.
The state response has been aggressive. In July 2026, 44 state attorneys general signed a letter to the CFTC arguing that the agency lacks authority over sports-related event contracts. The coalition's position is that state gambling laws, not federal commodity regulations, govern these markets.
Per DLA Piper's September 2026 analysis, the state-level landscape breaks down as follows:
The CFTC is itself suing states to assert exclusive jurisdiction, creating an unusual regulatory dynamic where the federal regulator is simultaneously proposing rules to govern the industry and litigating to establish that it has the authority to do so.
Kalshi raised $1 billion at a $22 billion valuation in March 2026, roughly doubling from its $11 billion Series E in November 2025, according to Bloomberg. The company is now seeking to raise at a $40 billion valuation before the end of Q3 2026. CEO Tarek Mansour has confirmed that Kalshi is preparing for an IPO but ruled out a 2026 listing. Federal lobbying disclosures show Kalshi spent $500,000 lobbying federal policymakers on "matters affecting prediction markets" in Q2 2026, more than any prior quarter.
Polymarket acquired CFTC-licensed exchange and clearinghouse QCEX for $112 million in July 2025, creating QCX LLC as a Designated Contract Market. The CFTC granted Polymarket regulatory clearance to re-enter the US market in September 2025, with the regulated US arm becoming fully operational after an Amended Order of Designation in November 2025. In April 2026, Polymarket filed for CFTC approval to bring US traders onto the same platform handling global volume, rather than operating a constrained US-only product.
Polymarket has expanded its compliance apparatus. Recent hires include Megan McGrath (formerly Robinhood) as chief compliance officer for the US exchange, Natalie Oblazny (formerly Coinbase) as head of regulatory affairs, Shana Bautista (former FBI official) as global head of investigations, and Paul Jordan (from Nasdaq) as chief risk officer for the US arm.
Three cases have tested prediction market surveillance systems in 2026.
White House teleprompter operator: Gabriel Perez, a White House teleprompter operator, used advance knowledge of President Trump's prepared speech text to trade Kalshi "mention markets." Kalshi's own surveillance systems flagged the irregular trading patterns. The CFTC ordered Perez to pay $107,539 in disgorgement plus a $65,000 civil penalty and banned him from trading for three years, per NBC News reporting from August 28, 2026.
MrBeast employee: In February 2026, Kalshi fined a MrBeast employee $20,000 for insider trading related to a YouTube live stream, per Fortune.
Military classified information: In April 2026, the Department of Justice indicted a US Army Master Sergeant for using classified information about a covert military operation to place bets on Polymarket.
In May 2026, the House Committee on Oversight and Government Reform examined Polymarket's safeguards against insider trading and access circumvention. The New York Times separately published an investigation identifying dozens of trades showing patterns consistent with insider activity across the platform.
These cases demonstrate that prediction markets face the same information asymmetry problems as traditional financial markets. The economic question is whether the current surveillance and enforcement framework is adequate for a market processing over $20 billion monthly.
The prediction market sector's value distribution differs materially from traditional exchange infrastructure. Revenue is concentrated in platform fees and spread capture, with Kalshi generating fee revenue from its dominant 92.1% market share position. The $40 billion target valuation implies the market is pricing Kalshi as exchange infrastructure comparable to traditional derivatives venues.
The sector's dependency on sports volume (approximately 85% of Kalshi's trading) creates regulatory concentration risk. If the Supreme Court upholds the Ninth Circuit's position that sports contracts fall under state gambling regulation, the platforms would need state-by-state licensing — a framework that could reduce addressable volume by as much as 30-40% depending on which states impose restrictions.
Conversely, if the Third Circuit's position prevails and the CFTC maintains exclusive jurisdiction, the platforms operate under a single federal regulator with established (if evolving) rules. The CFTC's June 2026 NPRM suggests the agency is building toward this model.
The sector also raises questions about economic utility beyond speculative trading. The CFTC's proposed three-factor test explicitly evaluates price discovery, information aggregation, and risk management functions — the same criteria applied to traditional derivatives. Whether prediction markets satisfy these criteria for sports events, political outcomes, and geopolitical scenarios remains contested.
Prediction markets in September 2026 present a paradox: explosive volume growth alongside deepening regulatory uncertainty. The sector has scaled from crypto-native experiment to a multi-billion-dollar monthly market in under two years, with Kalshi's $40 billion valuation target placing it alongside traditional exchange operators.
The resolution of the circuit split will determine whether these markets operate under a single federal framework or a patchwork of state gambling regulations. The CFTC's proposed rulemaking suggests the agency is building toward comprehensive federal oversight, but 44 state attorneys general and a Ninth Circuit ruling stand in the way.
The insider trading cases have introduced a second dimension of risk. Markets processing $20+ billion monthly with contracts tied to presidential speeches, military operations, and NFL games require surveillance infrastructure that neither the platforms nor the CFTC have demonstrated at scale. The economic value of prediction markets — as price discovery mechanisms, hedging tools, or information aggregators — will ultimately depend on whether the regulatory framework can establish the integrity standards that institutional capital requires.
The Supreme Court's eventual ruling will determine not just the fate of Kalshi and Polymarket, but whether prediction markets become a permanent feature of US financial infrastructure or revert to offshore, crypto-native operations outside regulatory reach.