The co-host qualification rules for Euro 2028 create tight balance around the 51.5% market price for all four nations—England, Scotland, Wales and the Republic of Ireland—making it through. UEFA’s format requires each to compete in separate groups, with only the top 20 advancing directly and two reserved spots awarded to the highest-ranked hosts who miss out on merit. England’s consistent elite ranking and recent results keep direct qualification probabilities near 99%, while Scotland, Wales and Ireland sit in the low-to-mid 90s in current simulations, leaving limited room for collective slippage. The December 2026 qualifying draw, 2026-27 Nations League outcomes and any early 2027 form shifts could quickly alter the implied probability if one or more hosts face unexpectedly difficult groups or results.