Prediction Markets Right Now: What to Watch as Kalshi and Polymarket Grow in Sports

Prediction markets are no longer a side story to sports. As of mid-June 2026, Kalshi has crossed $100 billion in lifetime traded volume and posted its first back-to-back billion-dollar days, fueled by the World Cup, the NBA Finals and the Stanley Cup Finals (Legal Sports Report). At the same time, the CFTC just dropped a 267-page rule proposal that would formally allow most sports contracts while drawing a hard line around the messiest ones (CNN Business). If you trade sports or prediction markets, this is the moment the rules of the road are being written. Here is what to watch.

How big have prediction markets actually gotten?

Big, and fast. Combined monthly volume on Kalshi and Polymarket more than quadrupled in eight months, from under $5 billion in September 2025 to roughly $24 billion in April 2026 (Congress.gov). Kalshi crossed $100 billion in lifetime volume on June 13, 2026, and its notional turnover hit $1.22 billion that Saturday and $1.24 billion the next day, the first single-day billion-dollar figures in the platform's history (DeFi Rate).

Sports are the engine. By February 2026, roughly 87% of the $39.7 billion Kalshi had traded over the prior year was on sports (CNBC). Polymarket, which exited the US in 2022, got federal approval in November 2025 and has been rolling its app back out stateside (CNBC). Keep one number in perspective. Notional volume is not profit, and it is not a win rate. It tells you attention and liquidity are flooding in. It tells you nothing about whether any individual trader is up.

What did the CFTC just propose, and why does it matter?

On June 10, 2026, the CFTC released a notice of proposed rulemaking that, for the first time, lays out which sports contracts are in and which are out (Axios). Allowed: final scores, point differentials, win-loss results, tournament advancement, and individual or team statistical performance over a game or a season (CNN Business).

What is off the table is just as telling. The proposal would disallow contracts on a single discrete play, like one pitch in baseball, one shot in hockey or one foul in basketball (CNN Business). It would also bar contracts on in-game physical fights, injuries, officiating decisions, and pre-collegiate events such as high school games (Axios). Notably, the CFTC set a low bar for "public interest," reasoning that even an NBA player-points market offers price discovery and therefore economic value (CNN Business).

This is a proposal, not law. The public comment period runs through July 27, 2026 (Cahill Gordon & Reindel). Expect the edges to move before anything is final.

The contracts the CFTC wants to ban are the single-play, injury and officiating markets. That tells you exactly where the integrity risk lives, and where to keep your guard up.

Who is fighting over the rules?

A lot of people, in a lot of courtrooms. In April 2026, a divided 3rd US Circuit panel ruled 2-1 that New Jersey could not stop Kalshi from offering sports event contracts in the state, finding the CFTC has exclusive jurisdiction over those contracts (CNBC). That is a meaningful win for the federal-preemption argument, but it is one circuit. Other cases are live, including a separate federal appeals court in San Francisco set to hear arguments (Holland & Knight).

There is also a tribal front. Four New Mexico tribes and pueblos, including the Mescalero Apache Tribe and the Pojoaque, Sandia and Isleta Pueblos, sued Kalshi, arguing the platform enables sports gambling on tribal land in violation of gaming compacts and federal Indian gaming law (Holland & Knight). The practical takeaway for traders: availability is still patchy and can change by state. Polymarket's relaunch, for instance, excludes states including AZ, IL, MA, MD, MI, MT, NJ, NV and OH (Dimers). Always confirm what is legal where you are.

What about the sportsbooks moving in?

The lines between sportsbook and exchange are blurring. FanDuel and DraftKings both launched prediction products in December 2025, with CME Group acting as the regulated exchange behind FanDuel Predicts and DraftKings Predictions operating as a CFTC-regulated product (Front Office Sports). DraftKings' contracts span 38 states, including sports contracts in places like California, Florida, Georgia and Texas, while FanDuel's are aimed at states without legal online sports betting (Front Office Sports). Parlay-style contracts are the next frontier, with Polymarket self-certifying parlay-style sports contracts with the CFTC (DeFi Rate).

Is there an integrity problem here?

Regulators clearly think the risk is real, and they are acting on it. The CFTC signed a data-sharing memorandum with Major League Baseball in March 2026 and another with the NHL on May 21, 2026, and is pursuing similar deals with every major US league to address insider trading from people with nonpublic information like injury status or lineups (CoinDesk). The Department of Justice has signaled it will prosecute insider trading on these markets (CoinDesk). Kalshi says it launched more than 200 investigations last year and already topped that in the first quarter of 2026 (CoinDesk).

For a regular trader, the honest read is this: thin, niche markets are where manipulation and information gaps hide. The deeper, headline markets are harder to game but still move fast on news.

What this means for how you trade

Treat prediction markets and sportsbooks as two tools, not one. A money-line market on Kalshi and the same game at a book can price differently, and the gap is information, not a free lunch. Watch the July 27 comment deadline, watch which contracts survive the final rule, and watch your own state's availability. None of this is a green light to chase. Prediction markets and sports betting are education and entertainment, not financial or wagering advice, and they are 21+ and jurisdiction-dependent. Bet only what you can afford to lose. If it stops being fun, the line is 1-800-GAMBLER.