diff --git a/app/Models/User.php b/app/Models/User.php
index ed0c201c..61d18b42 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -132,6 +132,11 @@ class User extends Authenticatable implements MustVerifyEmail
 
     private ?int $cachedOpenSinglePurchaseCount = null;
 
+    /**
+     * @var list<int>|null
+     */
+    private ?array $cachedAccessibleCompanyIds = null;
+
     /**
      * Findet einen User case-insensitive anhand der E-Mail. Single Source of
      * Truth für die E-Mail-basierte Auflösung (Magic-Link, Social-Login,
@@ -452,9 +457,19 @@ class User extends Authenticatable implements MustVerifyEmail
      */
     public function accessibleCompanyIds(): array
     {
-        return $this->ownedCompanies()->pluck('companies.id')
-            ->merge($this->companies()->pluck('companies.id'))
+        if ($this->cachedAccessibleCompanyIds !== null) {
+            return $this->cachedAccessibleCompanyIds;
+        }
+
+        // toBase() statt der Relation-pluck(): Eloquents Builder::pluck()
+        // hydratisiert sonst pro ID ein vollständiges Company-Model (bei
+        // Power-Usern mit zehntausenden Firmen ein massives Speicher-/Zeit-Leck).
+        // toBase() wendet die Global Scopes weiter an, liefert aber nur die
+        // nackten ID-Werte ohne Model-Hydration.
+        return $this->cachedAccessibleCompanyIds = $this->ownedCompanies()->toBase()->pluck('companies.id')
+            ->merge($this->companies()->toBase()->pluck('companies.id'))
             ->unique()
+            ->map(fn ($id): int => (int) $id)
             ->values()
             ->all();
     }
diff --git a/tests/Feature/PressReleaseAccessScopeTest.php b/tests/Feature/PressReleaseAccessScopeTest.php
index 76d248d8..a7ff8b99 100644
--- a/tests/Feature/PressReleaseAccessScopeTest.php
+++ b/tests/Feature/PressReleaseAccessScopeTest.php
@@ -67,6 +67,32 @@ test('accessibleBy excludes press releases of strangers and unrelated companies'
     expect($ids)->not->toContain($foreignPr->id);
 });
 
+test('accessibleCompanyIds returns owned and member company ids without duplicates', function () {
+    $user = User::factory()->create();
+    $owned = Company::factory()->create(['owner_user_id' => $user->id]);
+    $member = Company::factory()->create();
+    $member->users()->attach($user->id, ['role' => 'member']);
+    Company::factory()->create(); // fremde Firma
+
+    $ids = $user->accessibleCompanyIds();
+
+    expect($ids)->toEqualCanonicalizing([$owned->id, $member->id]);
+});
+
+test('accessibleCompanyIds does not hydrate Company models', function () {
+    $user = User::factory()->create();
+    Company::factory()->count(3)->create(['owner_user_id' => $user->id]);
+
+    $hydrated = 0;
+    Company::retrieved(function () use (&$hydrated): void {
+        $hydrated++;
+    });
+
+    $user->accessibleCompanyIds();
+
+    expect($hydrated)->toBe(0);
+});
+
 test('accessibleBy bypasses the portal global scope so own PMs are visible cross-portal', function () {
     $user = User::factory()->create();
     $pr = PressRelease::factory()->create([