diff --git a/codegen/sdk-codegen/aws-models/dynamodb-streams.2012-08-10.json b/codegen/sdk-codegen/aws-models/dynamodb-streams.2012-08-10.json
index f91ed65ed2b..0c0bfac1d6c 100644
--- a/codegen/sdk-codegen/aws-models/dynamodb-streams.2012-08-10.json
+++ b/codegen/sdk-codegen/aws-models/dynamodb-streams.2012-08-10.json
@@ -48,7 +48,7 @@
       }
     },
     "com.amazonaws.dynamodbstreams#AttributeValue": {
-      "type": "structure",
+      "type": "union",
       "members": {
         "SS": {
           "target": "com.amazonaws.dynamodbstreams#StringSetAttributeValue",
diff --git a/codegen/sdk-codegen/aws-models/dynamodb.2012-08-10.json b/codegen/sdk-codegen/aws-models/dynamodb.2012-08-10.json
index 830b9ed8cf4..e60cf8edd65 100644
--- a/codegen/sdk-codegen/aws-models/dynamodb.2012-08-10.json
+++ b/codegen/sdk-codegen/aws-models/dynamodb.2012-08-10.json
@@ -141,7 +141,7 @@
       }
     },
     "com.amazonaws.dynamodb#AttributeValue": {
-      "type": "structure",
+      "type": "union",
       "members": {
         "S": {
           "target": "com.amazonaws.dynamodb#StringAttributeValue",