UEFA Champions League 2026-27

The largest Champions League book in event contracts was not on this page. Polymarket's 2027 Champion market turns $1,065,193 in twenty-four hours—thirty-five times Kalshi's $30,605 on the identical question—and this workspace has been reading the title race off the smaller of the two books all season.

They do not agree. Barcelona is 16.5% on Polymarket against 18.5% on Kalshi. Arsenal is 15.5% against 13.5%. PSG is 14.5% against 16.5%. Real Madrid is 11.5% against 13.5%. Two-point spreads on four of the top five, all in different directions—which is what a genuinely contested pre-season looks like when neither book is anchoring to the other.

And the money is somewhere else again. Real Madrid at 11.5% took $35,130 on Polymarket, three times Arsenal's $11,690 and more than Barcelona and PSG combined, despite being fifth by price. On Kalshi, where daily flow is thin, the story is open interest: $238,331 on Barcelona and $189,878 on Real Madrid against a book that turns thirty thousand dollars a day.

Barcelona leads on price. Real Madrid leads on money, on both exchanges, by different measures.

The title race on both real-money books, side by side. Kalshi's on the left, Polymarket's on the right—same eight clubs at the top, roughly the same ordering, and no rung more than two and a half points apart.

What separates them is depth. Polymarket carries thirty-five times the daily flow; Kalshi carries the standing positions, with $818,000 of open interest across its top six against $30,605 of turnover. One book is where the season is being traded and the other is where it is being held.

Price, volume and open interest telling three different stories.

By price: Barcelona 18.5%, PSG 16.5%, Arsenal 13.5%, Real Madrid 13.5%, Bayern 13.5% (Kalshi).

By Polymarket volume: Real Madrid $35,130, Arsenal $11,690, Barcelona $9,979, Bayern $4,133, PSG $1,041.

By Kalshi open interest: Barcelona $238,331, Real Madrid $189,878, Arsenal $105,210, Bayern $90,585, PSG $86,603.

PSG is the divergence worth naming: second by price on Kalshi at 16.5%, and dead last of the five by Polymarket volume at $1,041. The book that prices it highest is the book nobody is trading it on.

The four contracts below are the two clubs the price favours, then the club the money favours, then the cross-exchange mirror on the same question.

Europe against the domestic league, where the pattern inverts.

Arsenal is 49.5% to win the Premier League and 13.5% to win Europe—a book that thinks the best team in England is a one-in-seven shot on the continent. That gap is wider than any of the other top-six clubs carry, and it is the cleanest statement in this stack about how the market rates depth of field.

The open-interest read underneath is stranger still. Tottenham at 2.5% holds $212,709, within striking distance of Arsenal's $235,691 at 49.5%—and Tottenham's leg outtraded Manchester City's at 17.5% on the day, $24,321 to $21,761. Chelsea at 10.5% holds $226,809, more than Manchester City at 17.5%. Rank the Premier League book by money and Arsenal barely leads it.

The other domestic books. Polymarket lists Ligue 1, Serie A and La Liga title markets alongside the Premier League runner-up board; all of them are thin—Ligue 1 turns $4,460—but they complete the cross-exchange picture on a continent where Kalshi carries the standing positions and Polymarket carries the flow.

• Thirty-five to one. Polymarket turns $1,065,193 on the Champions League against Kalshi's $30,605, and this workspace read the race off the smaller book until now. Any cross-exchange comparison built from Kalshi alone will systematically miss where European football is actually traded.
• Real Madrid is the money, Barcelona is the price. Fifth by price on Polymarket and first by volume at $35,130; second by Kalshi open interest at $189,878. Two exchanges, two different metrics, same answer—and neither of them is the favourite.
• PSG at 16.5% on $1,041. The second-priciest club in Kalshi's book took a thousand dollars on Polymarket. Either Kalshi is carrying stale marks or the flow has an opinion the marks have not caught up to.
• Arsenal: 49.5% at home, 13.5% in Europe. The widest domestic-to-continental gap of any top-six club, and a clean read on how the market weighs a twenty-club league against a thirty-six-team continental field.
• Tottenham holds $212,709 at 2.5%. Near-parity with Arsenal's open interest at twenty times the price, and the deepest sub-3% position in any football book this catalog covers. The Premier League board ranked by money looks nothing like the board ranked by price.