diff --git a/src/ert/analysis/_es_update.py b/src/ert/analysis/_es_update.py
index 78bec4c2edb..4fc3669d2f2 100644
--- a/src/ert/analysis/_es_update.py
+++ b/src/ert/analysis/_es_update.py
@@ -666,7 +666,7 @@ def analysis_IES(
             )
 
         # if the algorithm object is not passed, initialize it
-        if sies_smoother is not None:
+        if sies_smoother is None:
             parameter_ensemble = _all_parameters(
                 source_fs, iens_active_index, param_groups
             )