Pricing influx

Anyone know what going on with AC pricing the last 24 hours. Been looking to book a trip to STL from the east coast in June. Prices have gone up $350+ in the last 24 hours. Went from $546 to $914, it's now $3400 return for 2 people. Looked at the seat selection, the most seats selected on any given flight is 12 (I know not everyone pays for seat selection).