diff --git a/whois-commons/src/main/java/net/ripe/db/whois/common/rpsl/transform/FilterAuthFunction.java b/whois-commons/src/main/java/net/ripe/db/whois/common/rpsl/transform/FilterAuthFunction.java
index 1c919f11dc..74cc7acfeb 100644
--- a/whois-commons/src/main/java/net/ripe/db/whois/common/rpsl/transform/FilterAuthFunction.java
+++ b/whois-commons/src/main/java/net/ripe/db/whois/common/rpsl/transform/FilterAuthFunction.java
@@ -27,6 +27,7 @@
 
 import javax.annotation.Nonnull;
 import javax.annotation.concurrent.ThreadSafe;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
@@ -144,7 +145,7 @@ private List<RpslObject> getMaintainers(final RpslObject rpslObject) {
         maintainers.remove(rpslObject.getKey());
 
         if (maintainers.isEmpty()) {
-            return Collections.emptyList();
+            return new ArrayList<>();
         }
 
         return rpslObjectDao.getByKeys(ObjectType.MNTNER, maintainers);