diff --git a/app/Http/Requests/Concerns/ValidatesAccountDetailRules.php b/app/Http/Requests/Concerns/ValidatesAccountDetailRules.php
index ff753b30..cc0325d2 100644
--- a/app/Http/Requests/Concerns/ValidatesAccountDetailRules.php
+++ b/app/Http/Requests/Concerns/ValidatesAccountDetailRules.php
@@ -24,7 +24,10 @@ trait ValidatesAccountDetailRules
             ],
             'address' => ['nullable', 'string', 'max:500'],
             'purchase_price' => ['nullable', 'integer', 'min:0'],
-            'purchase_date' => ['nullable', 'date', 'before_or_equal:today'],
+            // Floor the date: a mistyped/ancient year would make the historical
+            // balance generator build a multi-century monthly series and OOM the
+            // queue worker (PHP-LARAVEL-49). 1900 rejects typos, not real assets.
+            'purchase_date' => ['nullable', 'date', 'after_or_equal:1900-01-01', 'before_or_equal:today'],
             'area_value' => ['nullable', 'numeric', 'min:0', 'max:99999999.99'],
             'area_unit' => ['nullable', 'string', Rule::in(['sqm', 'sqft', 'acres', 'hectares'])],
             'linked_loan_account_id' => [
@@ -52,7 +55,9 @@ trait ValidatesAccountDetailRules
         return [
             'annual_interest_rate' => ['nullable', 'numeric', 'min:0', 'max:100'],
             'loan_term_months' => ['nullable', 'integer', 'min:1', 'max:600'],
-            'loan_start_date' => ['nullable', 'date'],
+            // Floor the date for the same reason as purchase_date above: an
+            // ancient loan start date OOMs the balance generator (PHP-LARAVEL-49).
+            'loan_start_date' => ['nullable', 'date', 'after_or_equal:1900-01-01'],
             'original_amount' => ['nullable', 'integer', 'min:0'],
         ];
     }
diff --git a/app/Services/LoanBalanceGeneratorService.php b/app/Services/LoanBalanceGeneratorService.php
index 8e67119d..9713dd83 100644
--- a/app/Services/LoanBalanceGeneratorService.php
+++ b/app/Services/LoanBalanceGeneratorService.php
@@ -9,6 +9,15 @@ use Illuminate\Support\Str;
 
 class LoanBalanceGeneratorService
 {
+    /**
+     * Upsert historical balances in batches of this size. An old loan start
+     * date (which has no lower bound in validation) can produce a very long
+     * monthly series; building and upserting it all at once exhausts the queue
+     * worker's memory in Arr::map/flatten (PHP-LARAVEL-49). Batching bounds
+     * peak memory.
+     */
+    private const UPSERT_CHUNK_SIZE = 500;
+
     /**
      * Generate historical monthly balances from a loan's start date to today
      * using linear interpolation between the original amount owed and the
@@ -73,6 +82,25 @@ class LoanBalanceGeneratorService
                 'created_at' => $now,
                 'updated_at' => $now,
             ];
+
+            if (count($rows) >= self::UPSERT_CHUNK_SIZE) {
+                $this->upsertBalances($rows);
+                $rows = [];
+            }
+        }
+
+        $this->upsertBalances($rows);
+    }
+
+    /**
+     * Upsert a batch of balance rows, keyed by (account_id, balance_date).
+     *
+     * @param  list<array<string, mixed>>  $rows
+     */
+    private function upsertBalances(array $rows): void
+    {
+        if ($rows === []) {
+            return;
         }
 
         AccountBalance::upsert($rows, ['account_id', 'balance_date'], ['balance', 'updated_at']);
diff --git a/app/Services/RealEstateBalanceGeneratorService.php b/app/Services/RealEstateBalanceGeneratorService.php
index dbf3a8df..d203cdc4 100644
--- a/app/Services/RealEstateBalanceGeneratorService.php
+++ b/app/Services/RealEstateBalanceGeneratorService.php
@@ -9,6 +9,14 @@ use Illuminate\Support\Str;
 
 class RealEstateBalanceGeneratorService
 {
+    /**
+     * Upsert historical balances in batches of this size. An old purchase date
+     * (which has no lower bound in validation) can produce a very long monthly
+     * series; building and upserting it all at once exhausts the queue worker's
+     * memory in Arr::map/flatten (PHP-LARAVEL-49). Batching bounds peak memory.
+     */
+    private const UPSERT_CHUNK_SIZE = 500;
+
     /**
      * Generate historical monthly balances from purchase date to today
      * using linear interpolation between purchase price and current value.
@@ -73,6 +81,25 @@ class RealEstateBalanceGeneratorService
                 'created_at' => $now,
                 'updated_at' => $now,
             ];
+
+            if (count($rows) >= self::UPSERT_CHUNK_SIZE) {
+                $this->upsertBalances($rows);
+                $rows = [];
+            }
+        }
+
+        $this->upsertBalances($rows);
+    }
+
+    /**
+     * Upsert a batch of balance rows, keyed by (account_id, balance_date).
+     *
+     * @param  list<array<string, mixed>>  $rows
+     */
+    private function upsertBalances(array $rows): void
+    {
+        if ($rows === []) {
+            return;
         }
 
         AccountBalance::upsert($rows, ['account_id', 'balance_date'], ['balance', 'updated_at']);
diff --git a/tests/Feature/RealEstateTest.php b/tests/Feature/RealEstateTest.php
index 963ad0ac..65bc3f94 100644
--- a/tests/Feature/RealEstateTest.php
+++ b/tests/Feature/RealEstateTest.php
@@ -63,6 +63,26 @@ it('can create a real estate account with property details', function () {
     ]);
 });
 
+it('rejects a purchase date before the 1900 floor', function () {
+    actingAs($this->user);
+
+    // A pre-1900 (typically mistyped) date would make the historical balance
+    // generator build a multi-century monthly series and OOM the queue worker
+    // (PHP-LARAVEL-49). It must be rejected at validation.
+    $data = [
+        'name' => 'My Apartment',
+        'currency_code' => 'EUR',
+        'type' => AccountType::RealEstate->value,
+        'property_type' => PropertyType::Residential->value,
+        'purchase_price' => 25000000,
+        'purchase_date' => '1899-12-31',
+    ];
+
+    $response = $this->post(route('accounts.store'), $data);
+
+    $response->assertSessionHasErrors(['purchase_date']);
+});
+
 it('can create a real estate account with only required fields', function () {
     actingAs($this->user);
 
diff --git a/tests/Feature/Services/LoanBalanceGeneratorServiceTest.php b/tests/Feature/Services/LoanBalanceGeneratorServiceTest.php
index c76b5c98..b43bf5eb 100644
--- a/tests/Feature/Services/LoanBalanceGeneratorServiceTest.php
+++ b/tests/Feature/Services/LoanBalanceGeneratorServiceTest.php
@@ -10,6 +10,37 @@ beforeEach(function () {
     $this->service = app(LoanBalanceGeneratorService::class);
 });
 
+it('generates a long series across multiple upsert batches without gaps or duplicates', function () {
+    $this->travelTo(Carbon::parse('2026-06-15'));
+
+    $account = Account::factory()->loan()->create([
+        'user_id' => $this->user->id,
+    ]);
+
+    // ~46 years of monthly points is well over the internal upsert batch size,
+    // so this drives the chunked build/upsert path that stops the queue worker
+    // from exhausting memory on an ancient loan start date (PHP-LARAVEL-49).
+    $this->service->generateHistoricalBalances(
+        $account,
+        originalAmount: 15000000,
+        startDate: Carbon::parse('1980-01-15'),
+        currentBalance: 3000000,
+    );
+
+    $balances = $account->balances()->orderBy('balance_date')->get();
+    $dates = $balances->pluck('balance_date')->map->toDateString();
+
+    // Enough points to span more than one batch...
+    expect($balances->count())->toBeGreaterThan(500);
+    // ...and the batch boundaries must not drop or duplicate any date.
+    expect($dates->unique()->count())->toBe($balances->count());
+    // Endpoints stay anchored across the batched writes.
+    expect($dates->first())->toBe('1980-01-15');
+    expect($balances->first()->balance)->toBe(15000000);
+    expect($dates->last())->toBe('2026-06-15');
+    expect($balances->last()->balance)->toBe(3000000);
+});
+
 it('generates linearly interpolated balances from start date to today', function () {
     $this->travelTo(Carbon::parse('2026-03-15'));
 
diff --git a/tests/Feature/Services/RealEstateBalanceGeneratorServiceTest.php b/tests/Feature/Services/RealEstateBalanceGeneratorServiceTest.php
index 3195ee02..f1845fea 100644
--- a/tests/Feature/Services/RealEstateBalanceGeneratorServiceTest.php
+++ b/tests/Feature/Services/RealEstateBalanceGeneratorServiceTest.php
@@ -10,6 +10,37 @@ beforeEach(function () {
     $this->service = app(RealEstateBalanceGeneratorService::class);
 });
 
+it('generates a long series across multiple upsert batches without gaps or duplicates', function () {
+    $this->travelTo(Carbon::parse('2026-06-15'));
+
+    $account = Account::factory()->realEstate()->create([
+        'user_id' => $this->user->id,
+    ]);
+
+    // ~46 years of monthly points is well over the internal upsert batch size,
+    // so this drives the chunked build/upsert path that stops the queue worker
+    // from exhausting memory on an ancient purchase date (PHP-LARAVEL-49).
+    $this->service->generateHistoricalBalances(
+        $account,
+        purchasePrice: 10000000,
+        purchaseDate: Carbon::parse('1980-01-15'),
+        currentValue: 16000000,
+    );
+
+    $balances = $account->balances()->orderBy('balance_date')->get();
+    $dates = $balances->pluck('balance_date')->map->toDateString();
+
+    // Enough points to span more than one batch...
+    expect($balances->count())->toBeGreaterThan(500);
+    // ...and the batch boundaries must not drop or duplicate any date.
+    expect($dates->unique()->count())->toBe($balances->count());
+    // Endpoints stay anchored across the batched writes.
+    expect($dates->first())->toBe('1980-01-15');
+    expect($balances->first()->balance)->toBe(10000000);
+    expect($dates->last())->toBe('2026-06-15');
+    expect($balances->last()->balance)->toBe(16000000);
+});
+
 it('generates linearly interpolated balances from purchase date to today', function () {
     $this->travelTo(Carbon::parse('2026-03-15'));