I made a series of markets about whether Democrats or Republicans would win states in the 2020 election that they didn't win last time. However, I only included states that were sufficiently close in the 2020 election. This market resolves YES if the Democratic nominee wins any state or Electoral-voting district that Biden lost in 2020, except for the ones on the following list:
Here, by "Electoral-voting district", I am referring to D.C. and all Congressional districts that have their own electoral votes (those in Maine and Nebraska). The only ones not on the list that Democrats lost last time are Nebraska's first and third districts.
I will not count any new states or Electoral-voting districts towards the result of this market, since they were not part of the electoral results last time, so it doesn't make as much sense to say that they were flipped. For example, if Wisconsin started to apportion its electoral votes by district, I wouldn't resolve this YES on the basis of the Democrat winning one of those districts, even if Biden lost the plurality of the vote in it last time.