diff --git a/lisp/gnus/nnselect.el b/lisp/gnus/nnselect.el
index ecec705b32..f3537376db 100644
--- a/lisp/gnus/nnselect.el
+++ b/lisp/gnus/nnselect.el
@@ -899,12 +899,12 @@ nnselect-push-info
 		    (setq list (cdr all))))
 		;; now merge with the original list and sort just to
 		;; make sure
-		(setq list
-		      (sort (map-merge
-			     'list list
-			     (alist-get type (gnus-info-marks group-info)))
-			    (lambda (elt1 elt2)
-			      (< (car elt1) (car elt2))))))
+                (when-let ((marked (alist-get
+                                    type (gnus-info-marks group-info))))
+		 (setq list
+		       (sort (map-merge 'list list marked)
+			     (lambda (elt1 elt2)
+			       (< (car elt1) (car elt2)))))))
 	       (t
 		(setq list
 		      (gnus-compress-sequence