diff --git a/src/ert/analysis/_es_update.py b/src/ert/analysis/_es_update.py
index 0a36aec6dff..e8abe130c70 100644
--- a/src/ert/analysis/_es_update.py
+++ b/src/ert/analysis/_es_update.py
@@ -678,7 +678,7 @@ def adaptive_localization_progress_callback(
             Z.data[:] = 1
             Z = Z.tolil()
             Z.setdiag(1)
-            Z = sp.csc_matrix(Z)
+            Z = sp.sparse.csc_matrix(Z)
 
             Prec_u_sub = gspme.prec_sparse(
                 X_local.T,