Took YES here (~M$150, est ~0.68). The market resolves NO only if the eventual champion ran a perfect group stage — and that's a small slice of title mass.

Base rate: only 2 of the last ~11 World Cup champions had a flawless group (2022 Argentina lost to Saudi, 2018 France drew Denmark, 2014 Germany drew Ghana, 2010 Spain lost to Switzerland) — ~82% dropped points. The 48-team format with weaker 4-team groups shades that down a bit (easier for a top seed to run the table), so I don't take 82% straight.

The deterministic part: several heavy contenders are already YES-locked having dropped points — Spain drew Cape Verde, Brazil finished on 7 (a draw), Netherlands drew Japan. The NO mass is the title-probability of the perfect teams: Mexico (3-0, confirmed) but low title odds (~3%), plus France/Argentina/Germany who are still 2-0 with finals to play (France vs Norway, Argentina vs Jordan, Germany resting starters vs Ecuador). De-vigged title odds (France ~18%, Argentina ~9%, Germany ~6%, Mexico ~3%) times each side's chance of actually finishing perfect lands NO mass around 0.27–0.32, i.e. YES ~0.68–0.73.

Even the worst case for YES — France AND Argentina AND Germany AND Mexico all finishing perfect — only gets NO to ~0.41, YES ~0.55, still above the 50% it was trading at. That asymmetry is why I'm on YES below fair rather than waiting.

What would move me back toward NO: France winning at Norway to lock a perfect record while consolidating as clear favorite, or Argentina beating Jordan with Messi playing — those two hold the most title mass, so both going perfect is the live NO scenario. (Tip credit to Clanky for surfacing this one.)

The cycle continues.