diff --git a/.hgtags b/.hgtags
index 7ed2d35ecd85a61b7a76ebe2b2dc12209cb8967f..deefcbcc3ff3c9cac38ee3137488b9bb6472f4bd 100644
--- a/.hgtags
+++ b/.hgtags
@@ -143,3 +143,4 @@ e5ce704b8373f55f65e85f7aadf5600207209dff OpenOLAT 10.5.0
 f1a0784814fb3b4b6e707c528ea8e50002a72036 OpenOLAT 10.5.0
 0f69f7f504059f74d693436415dd0baf35693bf0 OpenOLAT 10.5.1
 6295b0af3c1c4d26c06bd8f79657cc3708bb330a OpenOLAT 10.5.2
+72c51b0cefe971948bd2335cd0a706e191b1b0fc OpenOLAT 10.5.3
diff --git a/src/main/java/org/olat/admin/user/UsermanagerUserSearchController.java b/src/main/java/org/olat/admin/user/UsermanagerUserSearchController.java
index 6135e815d2644d1540f0e6b28c18e79daa8e36cf..b60a15a8b8f3711b359d0e33d10b57ab3b6a3802 100644
--- a/src/main/java/org/olat/admin/user/UsermanagerUserSearchController.java
+++ b/src/main/java/org/olat/admin/user/UsermanagerUserSearchController.java
@@ -30,8 +30,10 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.olat.admin.user.bulkChange.UserBulkChangeManager;
 import org.olat.admin.user.bulkChange.UserBulkChangeStep00;
@@ -352,15 +354,12 @@ public class UsermanagerUserSearchController extends BasicController implements
 	 * @param tobeAddedIdentities
 	 */
 	public void addIdentitiesToSearchResult(UserRequest ureq, List<Identity> tobeAddedIdentities) {
+		Set<Identity> identitiesSet = new HashSet<>();
+		if(identitiesList != null) {
+			identitiesSet.addAll(identitiesList);
+		}
 		for (Identity toBeAdded : tobeAddedIdentities) {
-			boolean found = false;
-			for (Identity original : identitiesList) {
-				if (original.getKey().equals(toBeAdded.getKey())) {
-					found = true;
-					break;
-				}
-			}
-			if (!found) {
+			if (!identitiesSet.contains(toBeAdded)) {
 				identitiesList.add(toBeAdded);
 			}
 		}