diff --git a/packages/cli/package.json b/packages/cli/package.json
index b0d0bd4..2d227ac 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -59,6 +59,6 @@
   "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 46635dc..2ba9fef 100644
--- a/packages/tax-engine/package.json
+++ b/packages/tax-engine/package.json
@@ -79,6 +79,6 @@
     "@types/pdfkit": "^0.17.5",
     "tsup": "^8.5.1",
     "typescript": "^5.9.3",
-    "vitest": "^2.1.9"
+    "vitest": "^4.1.0"
   }
 }