diff --git a/README.md b/README.md
index 3ecd4190..51ab74e4 100644
--- a/README.md
+++ b/README.md
@@ -1115,5 +1115,5 @@ To allow for better optimizations, the compiler makes various assumptions.
 - Getting and setting properties on a plain object does not cause other side effects
   (using `.watch()` or `Proxy`).
 - Object properties are able to be added (not prevented with
-  `Object.defineProperty()`, `Object.defineProperties()`, `Object.freeze()` or
-  `Object.preventExtensions()`).
+  `Object.defineProperty()`, `Object.defineProperties()`, `Object.freeze()`,
+  `Object.preventExtensions()` or `Object.seal()`).