diff --git a/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt b/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt
index 2f3899293f..411bb95454 100644
--- a/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt
+++ b/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt
@@ -464,3 +464,8 @@ fun NotarisationRequest.generateSignature(serviceHub: ServiceHub): NotarisationR
 }
 
 val PublicKey.hash: SecureHash get() = encoded.sha256()
+
+/**
+ * Extension method for providing a sumBy method that processes and returns a Long
+ */
+fun <T> Iterable<T>.sumByLong(selector: (T) -> Long): Long = this.map { selector(it) }.sum()
diff --git a/core/src/main/kotlin/net/corda/core/utilities/KotlinUtils.kt b/core/src/main/kotlin/net/corda/core/utilities/KotlinUtils.kt
index 183b276fb8..675745f759 100644
--- a/core/src/main/kotlin/net/corda/core/utilities/KotlinUtils.kt
+++ b/core/src/main/kotlin/net/corda/core/utilities/KotlinUtils.kt
@@ -130,7 +130,3 @@ fun <V> Future<V>.getOrThrow(timeout: Duration? = null): V = try {
     throw e.cause!!
 }
 
-/**
- * Extension method for providing a sumBy method that processes and returns a Long
- */
-fun <T> Iterable<T>.sumByLong(selector: (T) -> Long): Long = this.map { selector(it) }.sum()
diff --git a/experimental/behave/src/scenario/kotlin/net/corda/behave/scenarios/steps/VaultSteps.kt b/experimental/behave/src/scenario/kotlin/net/corda/behave/scenarios/steps/VaultSteps.kt
index 4a2b7b3c3c..e5249a2bb2 100644
--- a/experimental/behave/src/scenario/kotlin/net/corda/behave/scenarios/steps/VaultSteps.kt
+++ b/experimental/behave/src/scenario/kotlin/net/corda/behave/scenarios/steps/VaultSteps.kt
@@ -4,7 +4,7 @@ import net.corda.behave.scenarios.ScenarioState
 import net.corda.behave.scenarios.api.StepsBlock
 import net.corda.behave.scenarios.helpers.Vault
 import net.corda.core.contracts.ContractState
-import net.corda.core.utilities.sumByLong
+import net.corda.core.internal.sumByLong
 import net.corda.finance.contracts.asset.Cash
 
 class VaultSteps : StepsBlock {