Trade can happen between two factions in the campaign mode. Trade agreements can be made in the diplomacy screen, allowing factions to exchange trade resources and generating extra income for both factions.
Trade may only be agreed between two factions if their capital cities are connected by road or waterways and generally only where relations are good. Overland routes cannot go through another faction's territory.
- If a trade agreement is agreed between factions, commerce will flow and bring in additional cash. Even without any resources produced, a trade agreement will generate income through tariffs. Tariffs are taxes imposed on foreign merchants that visit your realm to trade. These are not affected by tradable resources and provide a base income from every trade agreement you have.
- Owned resources will be automatically traded and provide income depending on production, number of trade partners and base value of a resource unit. Resource trade values can be found in the treasury menu by clicking the chest icon and navigating to the trade overview.
- While nearly every other option's value depends on context, trade agreements are strictly beneficial. You should strive to get as many trading agreements as possible for a steady trickle of income. As you expand (and provided your trading partners or you don't betray one another), the income will gradually increase.
- The number of resources and tariffs can be increased by building various infrastructure buildings, such as ports or Trading Depots. To max out your income, consider devoting one or two provinces exclusively to trading.
- The income from trade is a strategic consideration. Always check the income from trade from your target or ally before committing to a war. Shooting a hole through your budget is hardly conductive to a good war.
- Trade is crucial for High Elves (due to their espionage mechanic), Tomb Kings (due to their Mortuary Cult) and Dwarfs (due to The Forge). It is also fairly important for Empire and Bretonnia. Vampire Counts, Skaven, Lizardmen and Dark Elves can trade, but have a harder time due to diplomatic penalties with many factions. As mentioned above, Beastmen, Greenskin and Warriors of Chaos cannot trade.