The maximum efficiency loss on any difficulty is 65%.

You can hold certain amount of fiefs before tax inefficiency kicks in, and each fief increases inefficiency by a percent. Tax inefficiency depends on how many fiefs you personally own, and the campaign AI setting. The import items will no longer be available until caravans have returned them, which can take a rather long time.ДЄffects only rents and tariffs of all the player's fiefs. Also, when repeatedly purchasing imported goods from a town or village, the prosperity will eventually drop due to the lack of these goods. For villages, stop them from being raided, kill bandits if they do invade, build improvements, and complete quests given by the Village Elders. You can raise the prosperity of a town by making sure that its caravans reach their destinations, and by completing quests from its Guild Master. The prosperity of each fief also affects the amount of taxes they produce. Towns earn the most base taxes, villages and castles earn less.

A world of ice and fire warband guide