diff --git a/spec.bs b/spec.bs
index 59cc69252..22d5e55ea 100644
--- a/spec.bs
+++ b/spec.bs
@@ -2736,7 +2736,7 @@ from querying the server during an auction.
  To <dfn>compute the key hash of component ad</dfn> given an [=interest group ad=] |igAd|:
    1. Let |keyString| be the [=string/concatenation=] of the following strings separated with U+000A LF:
       1. "ComponentBid"
-      1. the [=URL serializer|serialization=] of |ad|.
+      1. the [=URL serializer|serialization=] of |igAd|.
     1. Return the [=SHA-256=] hash of the [=ASCII encoding=] of |keyString|.
 </div>