diff --git a/app/app/Services/LeadRouter.php b/app/app/Services/LeadRouter.php
index 3da56fa8..a8febfd2 100644
--- a/app/app/Services/LeadRouter.php
+++ b/app/app/Services/LeadRouter.php
@@ -1,4 +1,4 @@
-<?php
+<?php
 
 declare(strict_types=1);
 
@@ -76,6 +76,8 @@ class LeadRouter
                       SELECT 1 FROM tenants
                       WHERE tenants.id = snap.tenant_id
                         AND tenants.balance_rub > 0
+                        -- R-03: frozen tenant must not receive new leads (Stage 3 §4.3.1)
+                        AND tenants.frozen_by_balance_at IS NULL
                   )
                 ORDER BY snap.tenant_id,
                          (snap.daily_limit - projects.delivered_today) DESC,
@@ -110,6 +112,8 @@ class LeadRouter
                   SELECT 1 FROM tenants
                   WHERE tenants.id = snap.tenant_id
                     AND tenants.balance_rub > 0
+                    -- R-03: frozen tenant must not receive new leads (Stage 3 §4.3.1)
+                    AND tenants.frozen_by_balance_at IS NULL
               )
             ORDER BY snap.tenant_id,
                      (snap.daily_limit - projects.delivered_today) DESC,
diff --git a/app/tests/Feature/LeadRouter/FrozenFilterTest.php b/app/tests/Feature/LeadRouter/FrozenFilterTest.php
new file mode 100644
index 00000000..615b697d
--- /dev/null
+++ b/app/tests/Feature/LeadRouter/FrozenFilterTest.php
@@ -0,0 +1,152 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Models\Project;
+use App\Models\SupplierProject;
+use App\Models\Tenant;
+use App\Services\LeadRouter;
+use Carbon\Carbon;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+use Illuminate\Support\Facades\DB;
+use Tests\Concerns\SharesSupplierPdo;
+
+uses(DatabaseTransactions::class);
+uses(SharesSupplierPdo::class);
+
+beforeEach(function (): void {
+    Carbon::setTestNow('2026-05-28 12:00:00', 'Europe/Moscow'); // pre-21:00 MSK window
+    DB::statement("SELECT set_config('app.current_tenant_id', '0', true)");
+});
+
+afterEach(function (): void {
+    Carbon::setTestNow();
+});
+
+// ---------------------------------------------------------------------------
+// Case 1 — B-platform: frozen tenant must NOT receive leads (R-03 §4.3.1)
+// ---------------------------------------------------------------------------
+it('does not match B-platform project for frozen tenant (frozen_by_balance_at IS NOT NULL)', function () {
+    $tenant = Tenant::factory()->create([
+        'balance_rub'          => '500.00',
+        'frozen_by_balance_at' => now(), // frozen — R-03
+    ]);
+    $project = Project::factory()->for($tenant)->create([
+        'is_active'            => true,
+        'delivery_days_mask'   => 127,
+        'daily_limit_target'   => 10,
+        'delivered_today'      => 0,
+    ]);
+    $sp = SupplierProject::factory()->create(['platform' => 'B1']);
+    DB::table('project_supplier_links')->insert([
+        'project_id'          => $project->id,
+        'supplier_project_id' => $sp->id,
+        'platform'            => $sp->platform,
+        'subject_code'        => null,
+    ]);
+    DB::table('project_routing_snapshots')->insert([
+        'snapshot_date'       => '2026-05-28',
+        'project_id'          => $project->id,
+        'tenant_id'           => $tenant->id,
+        'daily_limit'         => 10,
+        'delivery_days_mask'  => 127,
+        'regions'             => '{}',
+        'signal_type'         => 'call',
+        'signal_identifier'   => null,
+        'sms_senders'         => null,
+        'sms_keyword'         => null,
+        'expected_volume'     => 10,
+        'delivered_count'     => 0,
+        'created_at'          => now(),
+    ]);
+
+    $matched = app(LeadRouter::class)->matchEligibleProjects($sp);
+
+    expect($matched)->toHaveCount(0); // R-03: frozen tenant must not receive leads
+});
+
+// ---------------------------------------------------------------------------
+// Case 2 — DIRECT-platform: frozen tenant must NOT receive leads
+// ---------------------------------------------------------------------------
+it('does not match DIRECT-platform project for frozen tenant (frozen_by_balance_at IS NOT NULL)', function () {
+    $tenant = Tenant::factory()->create([
+        'balance_rub'          => '500.00',
+        'frozen_by_balance_at' => now(), // frozen — R-03
+    ]);
+    $project = Project::factory()->for($tenant)->create([
+        'is_active'            => true,
+        'delivery_days_mask'   => 127,
+        'daily_limit_target'   => 10,
+        'delivered_today'      => 0,
+    ]);
+
+    // DIRECT supplier_project matches via signal_type + unique_key
+    $sp = SupplierProject::factory()->create([
+        'platform'    => 'DIRECT',
+        'signal_type' => 'call',
+        'unique_key'  => 'direct-test-frozen-001',
+    ]);
+
+    // Snapshot must carry signal_type + signal_identifier matching sp->unique_key
+    DB::table('project_routing_snapshots')->insert([
+        'snapshot_date'       => '2026-05-28',
+        'project_id'          => $project->id,
+        'tenant_id'           => $tenant->id,
+        'daily_limit'         => 10,
+        'delivery_days_mask'  => 127,
+        'regions'             => '{}',
+        'signal_type'         => 'call',
+        'signal_identifier'   => 'direct-test-frozen-001', // matches sp->unique_key
+        'sms_senders'         => null,
+        'sms_keyword'         => null,
+        'expected_volume'     => 10,
+        'delivered_count'     => 0,
+        'created_at'          => now(),
+    ]);
+
+    $matched = app(LeadRouter::class)->matchEligibleProjects($sp);
+
+    expect($matched)->toHaveCount(0); // R-03: frozen tenant must not receive leads
+});
+
+// ---------------------------------------------------------------------------
+// Case 3 (control) — B-platform, not frozen: MUST receive leads
+// ---------------------------------------------------------------------------
+it('matches B-platform project for non-frozen tenant (frozen_by_balance_at IS NULL)', function () {
+    $tenant = Tenant::factory()->create([
+        'balance_rub'          => '500.00',
+        'frozen_by_balance_at' => null, // NOT frozen — should match
+    ]);
+    $project = Project::factory()->for($tenant)->create([
+        'is_active'            => true,
+        'delivery_days_mask'   => 127,
+        'daily_limit_target'   => 10,
+        'delivered_today'      => 0,
+    ]);
+    $sp = SupplierProject::factory()->create(['platform' => 'B1']);
+    DB::table('project_supplier_links')->insert([
+        'project_id'          => $project->id,
+        'supplier_project_id' => $sp->id,
+        'platform'            => $sp->platform,
+        'subject_code'        => null,
+    ]);
+    DB::table('project_routing_snapshots')->insert([
+        'snapshot_date'       => '2026-05-28',
+        'project_id'          => $project->id,
+        'tenant_id'           => $tenant->id,
+        'daily_limit'         => 10,
+        'delivery_days_mask'  => 127,
+        'regions'             => '{}',
+        'signal_type'         => 'call',
+        'signal_identifier'   => null,
+        'sms_senders'         => null,
+        'sms_keyword'         => null,
+        'expected_volume'     => 10,
+        'delivered_count'     => 0,
+        'created_at'          => now(),
+    ]);
+
+    $matched = app(LeadRouter::class)->matchEligibleProjects($sp);
+
+    expect($matched)->toHaveCount(1); // control: non-frozen tenant with balance IS eligible
+});