diff --git a/externs/ima.js b/externs/ima.js
index 583c827cb6..0d7fd1ebb0 100644
--- a/externs/ima.js
+++ b/externs/ima.js
@@ -552,7 +552,7 @@ google.ima.dai.api.StreamRequest.prototype.format;
 /**
  * @type {Object.<
  *   google.ima.dai.api.OmidVerificationVendor,
- *   google.ima.dai.api.OmidAccessMode>}
+ *   (google.ima.dai.api.OmidAccessMode | undefined)>}
  */
 google.ima.dai.api.StreamRequest.prototype.omidAccessModeRules;