diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/container/UpgradeContainer.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/container/UpgradeContainer.kt
index e15f0ce64..0c0070806 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/container/UpgradeContainer.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/container/UpgradeContainer.kt
@@ -21,12 +21,18 @@ class UpgradeContainer(
 		get() = setOf()
 
 	private fun positiveDecimals(fn: (IMatteryUpgrade) -> Decimal, reducer: (Decimal, Decimal) -> Decimal): Decimal {
+		if (isEmpty)
+			return Decimal.ZERO
+
 		return iterator()
 			.map { (it.getCapability(MatteryCapability.UPGRADE)?.let(fn) ?: Decimal.ZERO).moreThanZero() * it.count }
 			.reduce(Decimal.ZERO, reducer)
 	}
 
 	private fun anyDecimals(fn: (IMatteryUpgrade) -> Decimal, reducer: (Decimal, Decimal) -> Decimal): Decimal {
+		if (isEmpty)
+			return Decimal.ZERO
+
 		return iterator()
 			.map { (it.getCapability(MatteryCapability.UPGRADE)?.let(fn) ?: Decimal.ZERO) * it.count }
 			.reduce(Decimal.ZERO, reducer)