diff --git a/pkg/coredata/membership_profile_filter.go b/pkg/coredata/membership_profile_filter.go
index ee53048bd..8a00cc491 100644
--- a/pkg/coredata/membership_profile_filter.go
+++ b/pkg/coredata/membership_profile_filter.go
@@ -153,8 +153,8 @@ AND (
 )
 AND (
 	CASE
-		WHEN @filter_user_name::text IS NOT NULL THEN
-			p.user_name = @filter_user_name::text
+		WHEN @filter_user_name::citext IS NOT NULL THEN
+			p.user_name = @filter_user_name::citext
 		ELSE TRUE
 	END
 )
diff --git a/pkg/coredata/migrations/20260309T120000Z.sql b/pkg/coredata/migrations/20260309T120000Z.sql
new file mode 100644
index 000000000..7488c3076
--- /dev/null
+++ b/pkg/coredata/migrations/20260309T120000Z.sql
@@ -0,0 +1,2 @@
+ALTER TABLE iam_membership_profiles
+ALTER COLUMN user_name TYPE CITEXT;