diff --git a/spec.bs b/spec.bs
index 85a3d56..2aaa252 100644
--- a/spec.bs
+++ b/spec.bs
@@ -580,7 +580,8 @@ Moreover, each {{SharedStorageWorklet}}'s [=global scopes|list of global scopes=
         |privateAggregationConfig|["{{SharedStoragePrivateAggregationConfig/maxContributions}}"]
         [=map/exists=], set |maxContributions| to
         |privateAggregationConfig|["{{SharedStoragePrivateAggregationConfig/maxContributions}}"].
-    1. If |maxContributions| is not a positive integer, set |maxContributions| to null.
+    1. If |maxContributions| is zero, return a new {{DOMException}} with name
+        "`DataError`".
     1. Return a new [=pre-specified report parameters=] with the items:
         : <a spec="private-aggregation-api" for="pre-specified report parameters">context ID</a>
         :: |contextId|