This market resolves YES if Formula 1 officially announces plans for a fourth Grand Prix in the USA before 2027 season begins (i.e., when the official 2027 season calendar is published).
To qualify:
The announcement must come from Formula 1 or Liberty Media (F1's owner)
The race must be planned to take place in the USA together with other 3 USA races in 3 different circuits. Holding a GP two times in the same USA circuit (maybe due to some local/global emergency) will not count.
The race must be intended to be part of the F1 World Championship calendar
The announcement only needs to state the intention to hold the race - the race itself does not need to take place before the resolution date.
Resolution will be based on official announcements from Formula 1: https://www.formula1.com/en/latest.html