Class A office space is the top tier in the US building classification: prime locations, modern systems, high-end lobbies and amenities, commanding the highest rents. Class B and C step down in age, spec and price.
The hybrid era produced a flight to quality: companies shrink their footprint but upgrade its class, betting that a better office earns the commute. The trade only works if the smaller space is sized on honest attendance data, since Class A waste is the most expensive waste there is.