I would like to buy a stock in the aftermarket today and then sell it when the market opens tomorrow. Is this a pattern day trade? Will it meet the criteria of a swing trade instead?
Buying a stock in the aftermarket today and then selling it tomorrow is not a day trade. A day trade is a round trip on the dame day.
Be that as it may, making one day trade does not make you a Pattern Day Trader. For that to occur, you need to execute more than three day trades (options and equities) in a rolling 5 business day period in a margin account, provided the number of day trades are more than six percent of your total trading activity for that same five-day period.