Index: binaries/data/mods/public/simulation/components/Trader.js
===================================================================
--- binaries/data/mods/public/simulation/components/Trader.js
+++ binaries/data/mods/public/simulation/components/Trader.js
@@ -164,15 +164,15 @@
 
 Trader.prototype.PerformTrade = function(currentMarket)
 {
-	let previousMarket = this.markets[(this.index+this.markets.length) % this.markets.length];
+	let previousMarket = this.markets[this.index];
 	if (previousMarket != currentMarket)  // Inconsistent markets
 	{
 		this.goods.amount = null;
-		return;
+		return INVALID_ENTITY;
 	}
 
 	this.index = ++this.index % this.markets.length;
-	let nextMarket = this.markets[(this.index+this.markets.length) % this.markets.length];
+	let nextMarket = this.markets[this.index];
 
 	if (this.goods.amount && this.goods.amount.traderGain)
 	{
@@ -209,11 +209,13 @@
 
 	let cmpPlayer = QueryOwnerInterface(this.entity);
 	if (!cmpPlayer)
-		return;
+		return INVALID_ENTITY;
 
 	this.goods.type = cmpPlayer.GetNextTradingGoods();
 	this.goods.amount = this.CalculateGain(currentMarket, nextMarket);
 	this.goods.origin = currentMarket;
+
+	return nextMarket;
 };
 
 Trader.prototype.GetGoods = function()
Index: binaries/data/mods/public/simulation/components/UnitAI.js
===================================================================
--- binaries/data/mods/public/simulation/components/UnitAI.js
+++ binaries/data/mods/public/simulation/components/UnitAI.js
@@ -5357,15 +5357,14 @@
 	}
 
 	let cmpTrader = Engine.QueryInterface(this.entity, IID_Trader);
-	cmpTrader.PerformTrade(currentMarket);
+	let nextMarket = cmpTrader.PerformTrade(currentMarket);
 	let amount = cmpTrader.GetGoods().amount;
-	if (!amount || !amount.traderGain)
+	if (!nextMarket || !amount || !amount.traderGain)
 	{
 		this.StopTrading();
 		return;
 	}
 
-	let nextMarket = cmpTrader.markets[cmpTrader.index];
 	this.order.data.target = nextMarket;
 
 	if (this.order.data.route && this.order.data.route.length)