diff --git a/package.json b/package.json
index f4c3f6e..3b30485 100644
--- a/package.json
+++ b/package.json
@@ -79,7 +79,7 @@
     "babel-plugin-transform-remove-console": "6.9.4",
     "babel-plugin-unassert": "3.2.0",
     "babel-preset-power-assert": "3.0.0",
-    "c8": "9.0.0",
+    "c8": "9.1.0",
     "esdoc": "1.1.0",
     "esdoc-ecmascript-proposal-plugin": "1.0.0",
     "esdoc-inject-script-plugin": "1.0.0",
diff --git a/yarn.lock b/yarn.lock
index b178718..9e3da69 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3405,10 +3405,10 @@ bundle-name@^3.0.0:
   dependencies:
     run-applescript "^5.0.0"
 
-c8@9.0.0:
-  version "9.0.0"
-  resolved "https://registry.yarnpkg.com/c8/-/c8-9.0.0.tgz#96f135754bbfc9fceb3c118970dcfd4a158de59d"
-  integrity sha512-nFJhU2Cz6Frh2awk3IW7wwk3wx27/U2v8ojQCHGc1GWTCHS6aMu4lal327/ZnnYj7oSThGF1X3qUP1yzAJBcOQ==
+c8@9.1.0:
+  version "9.1.0"
+  resolved "https://registry.yarnpkg.com/c8/-/c8-9.1.0.tgz#0e57ba3ab9e5960ab1d650b4a86f71e53cb68112"
+  integrity sha512-mBWcT5iqNir1zIkzSPyI3NCR9EZCVI3WUD+AVO17MVWTSFNyUueXE82qTeampNtTr+ilN/5Ua3j24LgbCKjDVg==
   dependencies:
     "@bcoe/v8-coverage" "^0.2.3"
     "@istanbuljs/schema" "^0.1.3"