diff --git a/css-typed-om/Overview.bs b/css-typed-om/Overview.bs
index 46a6236d..f612b27e 100644
--- a/css-typed-om/Overview.bs
+++ b/css-typed-om/Overview.bs
@@ -2477,7 +2477,7 @@ This list is the object's [=values to iterate over=].
     };
 
     [Exposed=(Window, Worker, PaintWorklet, LayoutWorklet),
-     Constructor(DOMMatrixReadOnly matrix, optional CSSMatrixComponentOptions options)]
+     Constructor(DOMMatrixReadOnly matrix, optional CSSMatrixComponentOptions options = {})]
     interface CSSMatrixComponent : CSSTransformComponent {
         attribute DOMMatrix matrix;
     };