diff --git a/packages/cli/package.json b/packages/cli/package.json
index a85573b..4a9904b 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -49,6 +49,6 @@
   "devDependencies": {
     "tsup": "^8.0.0",
     "typescript": "^5.4.0",
-    "vitest": "^2.1.9"
+    "vitest": "^4.1.0"
   }
 }
diff --git a/packages/tax-engine/package.json b/packages/tax-engine/package.json
index b5ce67c..8b82ad5 100644
--- a/packages/tax-engine/package.json
+++ b/packages/tax-engine/package.json
@@ -62,6 +62,6 @@
     "@types/pdfkit": "^0.17.5",
     "tsup": "^8.5.1",
     "typescript": "^5.9.3",
-    "vitest": "^2.1.9"
+    "vitest": "^4.1.0"
   }
 }