diff --git a/src/PIL/_typing.py b/src/PIL/_typing.py
index 6aba6ebe9..f1889f07e 100644
--- a/src/PIL/_typing.py
+++ b/src/PIL/_typing.py
@@ -70,6 +70,7 @@ Anchor = Literal[
     "rd",
     "sa",
     "st",
+    "sm",
     "ss",
     "sb",
     "sd",