Prediction Markets Hit Record $50.6bn in July as Kalshi Takes 74.5%

The headline total barely moved on June. Underneath it, Kalshi added roughly a fifth to its volume while Polymarket's international book fell 26%, and the World Cup that drove the quarter ended on 19 July. August is the first clean read.

• Combined volume across Kalshi, Polymarket and Polymarket US reached a record $50.6 billion in July, according to data reported by The Block
• Kalshi accounted for $37.7 billion, roughly 74.5% of the total, extending the lead it built during the tournament
• Polymarket's international platform fell 26% month on month to $7.9 billion, while its US arm rose 54% to $5 billion
• The 2026 World Cup, which ran from 11 June to the 19 July final, generated $20 billion in on-chain prediction market volume since January, according to a Chainalysis report published on 31 July
• Kalshi's market on the Spain against Argentina final alone recorded approximately $1.89 billion

A Record That Is Really a Redistribution

Prediction markets recorded their largest month on record in July, with combined volume across Kalshi, Polymarket and Polymarket US reaching $50.6 billion, according to figures reported by The Block.

Set against June, when iGaming Times reported the sector passing $50 billion for the first time, the headline barely moved. What moved was the composition.

Kalshi traded $37.7 billion, about 74.5% of all volume, up from roughly $31 billion in June. Polymarket's international platform went the other way, falling 26% month on month to $7.9 billion. Its US arm, by contrast, rose 54% to $5 billion.

So a flat top line conceals a decisive shift. One venue now takes close to three-quarters of the market, and the only part of Polymarket's business that grew was the one operating inside a US regulatory perimeter.

The Tournament That Produced the Quarter Has Finished

The 2026 World Cup is the obvious driver, and its timing matters for reading these numbers. The tournament ran from 11 June to the final on 19 July, which places it across both record months.

According to a Chainalysis report published on 31 July, the World Cup generated $20 billion in on-chain prediction market volume since January. Kalshi's market on the final between Spain and Argentina recorded approximately $1.89 billion on its own, after Spain won 1-0.

That single fixture accounted for a meaningful share of the month, which is the clearest indication yet of how concentrated this volume is around marquee events rather than spread across a continuous betting calendar.

A Flat Headline Hiding a 74.5% Share Is the Real Story

Reporting these months as consecutive records misses what changed. June and July are effectively the same size, and in the space between them Kalshi added around $6.7 billion of monthly volume while Polymarket's international book shed roughly $2.9 billion. A market that is not growing in aggregate but is consolidating rapidly behind one venue behaves very differently from one that is expanding: it means Kalshi's gains are increasingly coming from its competitor rather than from new demand. For sportsbooks watching this space, that distinction matters. A growing prediction-market sector takes customers from betting; a consolidating one is mostly rearranging the customers it already has.

The Only Growing Polymarket Is the Regulated One

The divergence inside Polymarket is the most instructive number here. Its international platform, which serves users outside the US perimeter, contracted 26%, while its US arm grew 54%. That runs against the intuition that offshore venues enjoy an advantage from lighter regulation, and it arrives in the same month that European regulators have been closing the offshore route: as iGaming Times reported this week, Denmark has blocked Polymarket alongside 97 other sites following a court ruling, and the Netherlands has taken its own action. If the pattern holds, the commercial argument for operating outside a licensed perimeter is weakening at exactly the point the legal one is.

August Is the Number That Actually Tells You Something

Two consecutive records built around a World Cup say very little about underlying demand, because the tournament ended on 19 July and took its fixture list with it. The August figure is the first month in this cycle without a global sporting event inflating it, and it is the one worth waiting for. If volume holds anywhere near $50 billion without a World Cup, the argument that event contracts have become a permanent competitor to sportsbooks gets considerably stronger. If it falls back sharply, then what these two months measured was a tournament, not a structural shift, and a good deal of the commentary written about them will need revising.

The sector has just posted its largest month. Whether that reflects a market or a fixture list will be clear in about a fortnight.