The rolling week in prediction markets

The board moved.Here’s what mattered.

A daily review of the largest verified seven-day probability moves and the clearest current price differences across Kalshi and Polymarket.

PredictionCompare EditorialJul 11–18 · updated daily

The defining seven-day move

Spain reshaped the World Cup board.

🇪🇸

Spain to win the 2026 World Cup moved from approximately 21% to 59% over the previous seven days—the largest absolute change among the verified high-volume matched markets available for today’s edition.

Why it movedSpain’s 2–0 semifinal win over France on July 14 secured a place in the World Cup final. Advancing from the final four to the title match is the clear event-level reason its championship probability rose. FIFA match report ↗

+38 ptsReliable-window probability move21% → 59%Polymarket YES history

Jul 11Jul 18

Largest moves

Three markets that changed.

Movement uses stable Polymarket YES observations over the rolling window ending July 18, 2026. Isolated opening ticks are excluded.

01 · World Cup🇦🇷

Argentina to win the 2026 World Cup

+23 pts

18% → 40% · over the previous seven days

Why it movedArgentina’s 2–1 semifinal win over England on July 15 secured a place in the World Cup final. Advancing from the final four to the title match is the clear event-level reason its championship probability rose. FIFA match report ↗

02 · Golf⛳

Jon Rahm to win the 2026 Open Championship

−15 pts

18% → 2% · over 5 days of reliable trading history

Why it movedLive tournament results replaced pre-event uncertainty: at the latest verified update, Jon Rahm was T20 at -3 after round 3, 5 shots behind Ryan Fox at -8. That leaderboard position is the clearest verified context for the repricing. ESPN leaderboard ↗

03 · Golf⛳

Shane Lowry to win the 2026 Open Championship

−15 pts

16% → 1% · over 5 days of reliable trading history

Why it movedLive tournament results replaced pre-event uncertainty: at the latest verified update, Shane Lowry was T20 at -3 after round 3, 5 shots behind Ryan Fox at -8. That leaderboard position is the clearest verified context for the repricing. ESPN leaderboard ↗

Best current edge

Where prices disagree now.

This is a current cross-venue comparison—not a prediction that either venue is correct.

Matt Heilala to advance from the 2026 Alaska Governor primary

Verified identical settlement
$4K total matched

KalshiYES price

9%$100 pays$1,111

PolymarketBetter price

2%$100 pays$5,000

Matt Heilala · same $100 on YESPolymarket pays $3,889 more than Kalshi on a $100 YES position for Matt HeilalaCompare the live market →

Behind this edition

What made the cut.

A compact audit trail for the edition—kept separate from the market stories above.

Verified coverage

201 price histories checked.

Spanning 40 distinct parent markets in this edition.

Quality control

Only stable moves make the cut.

Isolated opening quotes are removed before ranking, so one noisy first tick does not become a story.

Previous editions