Prediction markets processed $14.1 billion in combined weekly volume during the week of September 7-13, 2026, according to DeFi Rate data — a figure that would have constituted an entire month's trading as recently as late 2025. Combined monthly volume across Kalshi and Polymarket grew from under...
"I'm joining Shayne and the leadership team to put the capital strategy and operating discipline in place to move quickly at scale." — Warren Jenson, CFO of Polymarket and former CFO of Amazon
Prediction markets processed $14.1 billion in combined weekly volume during the week of September 7-13, 2026, according to DeFi Rate data — a figure that would have constituted an entire month's trading as recently as late 2025. Combined monthly volume across Kalshi and Polymarket grew from under $5 billion in September 2025 to approximately $24 billion by April 2026, per Pew Research Center analysis. Kalshi now commands 92.1% of the two-platform market, trading $12.98 billion in the week ending September 13 versus Polymarket's $1.11 billion.
The velocity of capital formation has attracted institutional infrastructure. On September 10, Polymarket hired Warren Jenson — four-time Fortune 500 CFO, most recently at Amazon — as its first chief financial officer, part of an effort to raise $1 billion at a $21 billion valuation. Kalshi closed a $1 billion Series F in May at $22 billion, led by Coatue with participation from Sequoia, Andreessen Horowitz, and Morgan Stanley. On September 17, the CFTC issued a no-action letter exempting "passive software" providers from broker registration, opening the door for any app to embed prediction market access without obtaining a separate license.
What remains unresolved is whether the sector's economics — dominated by sports contracts — can survive the regulatory tension between the CFTC's commodity framework and state gambling laws. The first federal insider-trading enforcement action in prediction markets, settled in September for $172,000, signals regulators view these platforms as financial infrastructure, not entertainment.
Monthly trading volume on prediction markets hovered at approximately $1.2 billion through early 2025, according to TRM Labs. The inflection point came in October 2024 when a federal court ruled that Kalshi could legally offer election contracts, and the platform relaunched 32 days before the presidential election.
By January 2025, Kalshi added sports event contracts in all 50 states. A March 2025 partnership brought Kalshi's markets to Robinhood's 27 million funded brokerage accounts. Volume escalated from under $5 billion per month in September 2025 to over $20 billion by January 2026, per TRM Labs data.
On February 28, 2026, Polymarket set a single-day volume record of $425 million, surpassing the prior high from U.S. Election Day 2024. That spike was driven by geopolitical markets: a "Will US strike Iran" cluster generated $252.7 million in total volume across 23 sub-markets, with the "Khamenei out by Feb 28" contract surging from $930,000 to $39 million in 24 hours — a 1,275x increase on the YES token, with 45,638 unique wallets participating, according to TRM Labs.
By April 2026, combined monthly volume reached approximately $24 billion, according to Pew Research Center. Over the trailing year through September 2026, Kalshi traded $39.7 billion and Polymarket traded $36.2 billion.
The competitive dynamics between the two dominant platforms have shifted materially.
Kalshi operates as a CFTC-regulated designated contract market. It closed a $1 billion Series F in May 2026 at a $22 billion valuation, led by Coatue Management with participation from Sequoia Capital, Andreessen Horowitz, IVP, Paradigm, Morgan Stanley, and ARK Invest. Monthly volume reached $16.81 billion in May 2026. Annualized revenue stood at approximately $2 billion as of June 2026, up from $735 million in December 2025. Sports contracts represent roughly 75% of Kalshi's volume; Kalshi recorded $871 million in trading volume on Super Bowl Sunday alone.
Polymarket operates offshore and claims to block U.S. users on its primary exchange, though it has acquired a smaller CFTC-approved exchange available to U.S. customers, creating a dual-exchange structure. ICE/NYSE invested up to $2 billion in Polymarket in October 2025 at an $8 billion valuation. On September 10, 2026, the company hired Warren Jenson as its first CFO, pursuing a $1 billion raise at a $21 billion valuation.
The market share gap has widened considerably. During the week of September 7-13, Kalshi generated $12.98 billion in volume (92.1% share) versus Polymarket's $1.11 billion (7.9%). In non-sport categories, Kalshi drew $9.6 billion in weekly volume versus Polymarket's $344.2 million. Until early June 2026, volumes were more balanced; Polymarket held the lead through much of 2025.
TRM Labs wallet-level analysis of January-March 2026 activity reveals a stratified user base:
| Segment | Share of Activity | Volume | Median Trade Size | |---------|-------------------|--------|-------------------| | Mid-frequency traders (11-1,000 trades) | 44.7% | $869M | — | | High-frequency market makers (10,000+ trades) | 35.2% | $774M | — | | First-time bettors | <0.2% | $3.5M | — |
Casual participants placed a median trade of $30. Active traders placed a median trade of $12, indicating high-frequency, small-ticket strategies. Unique wallets tripled to 840,000 by February 2026.
Profitability concentration is extreme. The top wallet earned $6.2 million across diverse markets. The second-highest earner generated $3.35 million from Oscars markets via algorithmic market-making. A macro specialist earned $3.26 million from Fed rate decision contracts.
The CFTC has taken a series of actions in 2026 that collectively establish prediction markets as a recognized asset class within U.S. derivatives law.
January 29, 2026: Chairman Michael Selig announced the agency would write rules governing prediction markets, scrapping a prior proposed rule that would have prohibited trades on sports and politics.
June 10, 2026: The CFTC issued a proposed rule modifying Rule 40.11 and establishing a new procedural framework for event contracts under Section 5c(c)(5)(C) of the Commodity Exchange Act. The rule defines which types of event contracts can be listed on CFTC-registered markets and sets "public interest determination" criteria.
September 17, 2026: The CFTC's Market Participants Division issued Staff Letter 26-25, a no-action letter exempting "passive software" providers from introducing broker registration. The letter draws a clear line: custody of user assets triggers registration requirements; code alone does not. This expands relief first granted to crypto wallet provider Phantom Technologies in March 2026 under Staff Letter 26-09.
State-level resistance persists. Several states view prediction markets, particularly sports contracts, as gambling subject to state regulation, creating jurisdictional friction that remains unresolved.
The first federal insider-trading enforcement action in prediction markets concluded in September 2026. Gabriel Perez, a former White House teleprompter operator, agreed to pay $172,000 to settle CFTC charges. According to the agency, Perez misappropriated material, nonpublic information obtained through his job to trade "presidential mention market" contracts on Kalshi — event contracts that pay out based on specific words or phrases a president uses in a speech.
Between December 2025 and February 2026, Perez generated $107,539.02 in profits. The settlement requires disgorgement of those profits plus a $65,000 civil penalty and a three-year trading ban from prediction markets.
The Department of Justice and CFTC brought the case jointly in April 2026, according to Dentons. The case establishes that trading on nonpublic information obtained through a position of trust constitutes fraud in the context of event contracts — the same legal standard applied to insider trading in securities and commodity futures.
The case also spotlights "mention markets," a contract subcategory where payouts hinge on whether a public figure says a specific word. These markets have drawn CFTC scrutiny as the agency assesses whether they serve a price-discovery function or constitute entertainment products.
Distribution is the current competitive battleground. Three developments in September 2026 illustrate the dynamics:
Robinhood-OG.com deal (September 8): Robinhood Markets took equity stakes in Crypto.com and its prediction-market spinoff OG.com, routing certain football event contracts through OG.com's CFTC-regulated infrastructure. Robinhood continues routing other contracts to Kalshi, ForecastEx, and Rothera, diversifying its exchange partner base.
Yahoo Finance-Polymarket split (September 18): Yahoo Finance ended its six-month data partnership with Polymarket, according to Bloomberg. The deal, struck in November 2025, made Polymarket the exclusive prediction market data provider on Yahoo Finance. The hub was taken down in April 2026 with the formal termination following in September. A Yahoo spokesperson said Polymarket remains an advertising partner, and Yahoo remains "open to similar types of partnership."
CFTC passive software letter (September 17): Staff Letter 26-25 allows any non-custodial software provider to embed access to CFTC-regulated prediction markets, collect revenue-sharing fees, and avoid introducing broker registration. The practical effect: prediction market access can be bundled into wallets, trading apps, and social platforms without regulatory friction, provided the software provider does not hold user funds.
Both platforms are expanding beyond traditional binary event contracts.
Polymarket Perps (September 3): Polymarket launched perpetual futures contracts — never-expiring derivatives — across 67 markets including Bitcoin, crude oil (Brent and WTI), individual stocks, equity indexes, gold, and silver. Leverage of up to 20x is available. The product is limited to international users. The move puts Polymarket in direct competition with crypto derivatives exchanges and, potentially, with traditional commodity futures platforms.
Kalshi commodity expansion: Kalshi is also seeking to enter traditional commodity markets, competing with Polymarket's perpetual futures offering.
The product expansions indicate both platforms view binary event contracts as a customer acquisition mechanism, not a terminal business model. The longer-term play appears to be full-spectrum derivatives access — prediction markets, perpetual futures, and potentially options — through a single interface.
Prediction markets have reached a scale where they generate more weekly volume than many mid-cap token ecosystems generate in a month. The $14.1 billion weekly figure is not a speculative proxy — it represents settled contracts on outcomes with definite resolution dates. The CFTC's regulatory actions in 2026, culminating in the September 17 passive software letter, indicate the agency has decided to regulate prediction markets as financial infrastructure rather than restrict them.
The unresolved tension is structural. Kalshi's economics are 75% dependent on sports contracts. State gambling regulators view these products differently than the CFTC does. Polymarket's dual-exchange structure — offshore for international users, CFTC-regulated for U.S. users — carries its own regulatory complexity. The Yahoo Finance partnership dissolution suggests mainstream distribution partnerships remain fragile.
The insider-trading precedent matters more than its $172,000 price tag suggests. By applying commodity fraud standards to event contracts, the CFTC has established that prediction markets carry the same legal obligations as traditional derivatives. Market participants — particularly those with access to nonpublic information relevant to contract outcomes — are now on notice.
What the data shows: prediction markets have achieved product-market fit. What the data does not show: whether the current economics — dominated by sports betting volume flowing through a commodity futures wrapper — represent a durable business model or a regulatory arbitrage with an expiration date.