diff --git a/app/Console/Commands/ResetDemoAccountCommand.php b/app/Console/Commands/ResetDemoAccountCommand.php
index 1bf78583..604a3653 100644
--- a/app/Console/Commands/ResetDemoAccountCommand.php
+++ b/app/Console/Commands/ResetDemoAccountCommand.php
@@ -276,7 +276,7 @@ class ResetDemoAccountCommand extends Command
         $balances = [];
 
         for ($i = 0; $i <= 12; $i++) {
-            $date = now()->subMonths($i)->endOfMonth();
+            $date = now()->subMonthsNoOverflow($i)->endOfMonth();
 
             if ($i === 0) {
                 $date = now();
diff --git a/app/Http/Controllers/Api/CashflowAnalyticsController.php b/app/Http/Controllers/Api/CashflowAnalyticsController.php
index 99dfe7a1..ed24ac44 100644
--- a/app/Http/Controllers/Api/CashflowAnalyticsController.php
+++ b/app/Http/Controllers/Api/CashflowAnalyticsController.php
@@ -67,7 +67,7 @@ class CashflowAnalyticsController extends Controller
         $userId = $request->user()->id;
 
         $end = Carbon::now()->endOfMonth();
-        $start = Carbon::now()->subMonths($months - 1)->startOfMonth();
+        $start = Carbon::now()->subMonthsNoOverflow($months - 1)->startOfMonth();
 
         $data = [];
         $current = $start->copy();
diff --git a/tests/Feature/AccountControllerTest.php b/tests/Feature/AccountControllerTest.php
index 98fb1cad..366b7113 100644
--- a/tests/Feature/AccountControllerTest.php
+++ b/tests/Feature/AccountControllerTest.php
@@ -167,7 +167,7 @@ test('account balance evolution returns data for single account', function () {
     ]);
 
     $response = $this->getJson('/api/dashboard/account/'.$account->id.'/balance-evolution?'.http_build_query([
-        'from' => now()->subMonths(2)->startOfMonth()->toDateString(),
+        'from' => now()->subMonthsNoOverflow(2)->startOfMonth()->toDateString(),
         'to' => now()->endOfMonth()->toDateString(),
     ]));
 
diff --git a/tests/Feature/CashflowAnalyticsTest.php b/tests/Feature/CashflowAnalyticsTest.php
index 2dec35bb..bc6432bb 100644
--- a/tests/Feature/CashflowAnalyticsTest.php
+++ b/tests/Feature/CashflowAnalyticsTest.php
@@ -223,14 +223,14 @@ test('cashflow trend returns monthly data for specified months', function () {
             'account_id' => $account->id,
             'category_id' => $incomeCategory->id,
             'amount' => 100000 + ($i * 10000),
-            'transaction_date' => now()->subMonths($i),
+            'transaction_date' => now()->subMonthsNoOverflow($i),
         ]);
         Transaction::factory()->create([
             'user_id' => $this->user->id,
             'account_id' => $account->id,
             'category_id' => $expenseCategory->id,
             'amount' => -(50000 + ($i * 5000)),
-            'transaction_date' => now()->subMonths($i),
+            'transaction_date' => now()->subMonthsNoOverflow($i),
         ]);
     }
 
diff --git a/tests/Feature/DashboardAnalyticsTest.php b/tests/Feature/DashboardAnalyticsTest.php
index 108d72f7..78c2c3a1 100644
--- a/tests/Feature/DashboardAnalyticsTest.php
+++ b/tests/Feature/DashboardAnalyticsTest.php
@@ -211,7 +211,7 @@ test('net worth evolution returns monthly data points with per-account balances'
     ]);
 
     $response = $this->getJson('/api/dashboard/net-worth-evolution?'.http_build_query([
-        'from' => now()->subMonths(2)->startOfMonth()->toDateString(),
+        'from' => now()->subMonthsNoOverflow(2)->startOfMonth()->toDateString(),
         'to' => now()->endOfMonth()->toDateString(),
     ]));