diff --git a/app/Services/Banking/BinanceBalanceSyncService.php b/app/Services/Banking/BinanceBalanceSyncService.php
index 314d9571..b16e0e9a 100644
--- a/app/Services/Banking/BinanceBalanceSyncService.php
+++ b/app/Services/Banking/BinanceBalanceSyncService.php
@@ -95,7 +95,18 @@ class BinanceBalanceSyncService
     }
 
     /**
-     * Fetch historical snapshots and convert each day's balances using the currency conversion API.
+     * Rebuild past daily balances from Binance's own daily snapshots.
+     *
+     * Each snapshot carries `totalAssetOfBtc`: what Binance valued the whole
+     * spot account at, on that day. One BTC->fiat conversion turns it into the
+     * user's currency, and BTC is the one ticker the rate provider always
+     * covers.
+     *
+     * The alternative - re-pricing each holding ourselves - needs a dated price
+     * per asset, and the only dated source here is a fiat rate provider that
+     * knows almost no altcoins. Anything it could not price was dropped from
+     * the day's total, so a portfolio of tokens it does not carry produced a
+     * chart history far below what the user actually held.
      *
      * @return bool Whether any API calls were made
      */
@@ -121,36 +132,36 @@ class BinanceBalanceSyncService
         }
 
         $count = 0;
-        $skippedAssets = [];
+        $unpricedDays = 0;
+        $daysWithoutValuation = 0;
 
         foreach ($snapshots as $snapshot) {
             $updateTime = $snapshot['updateTime'] ?? null;
-            $balances = $snapshot['data']['balances'] ?? [];
+            $btcValue = $snapshot['data']['totalAssetOfBtc'] ?? null;
+
+            if ($updateTime === null) {
+                continue;
+            }
+
+            // The whole valuation now rests on this one field, so a Binance
+            // response that stops carrying it must be visible rather than look
+            // like a day they simply had no snapshot for.
+            if ($btcValue === null) {
+                $daysWithoutValuation++;
 
-            if ($updateTime === null || empty($balances)) {
                 continue;
             }
 
             $date = Carbon::createFromTimestampMs($updateTime)->toDateString();
-            $totalValue = 0.0;
+            $btcValue = (float) $btcValue;
+            $totalValue = $this->currencyConverter->convert('BTC', $targetCurrency, $btcValue, $date);
 
-            foreach ($balances as $balance) {
-                $asset = $balance['asset'];
-                $quantity = (float) ($balance['free'] ?? 0) + (float) ($balance['locked'] ?? 0);
+            // A held-but-unpriceable day would land as a zero balance and read as
+            // a portfolio that briefly vanished, so leave the day alone instead.
+            if ($btcValue > 0 && $totalValue <= 0) {
+                $unpricedDays++;
 
-                if ($quantity <= 0 || isset($skippedAssets[$asset])) {
-                    continue;
-                }
-
-                $converted = $this->currencyConverter->convert($asset, $targetCurrency, $quantity, $date);
-
-                if ($converted == 0.0) {
-                    $skippedAssets[$asset] = true;
-
-                    continue;
-                }
-
-                $totalValue += $converted;
+                continue;
             }
 
             $account->balances()->updateOrCreate(
@@ -165,7 +176,8 @@ class BinanceBalanceSyncService
             'account_id' => $account->id,
             'days_synced' => $count,
             'currency' => $targetCurrency,
-            ...($skippedAssets ? ['skipped_assets' => array_keys($skippedAssets)] : []),
+            ...($unpricedDays ? ['unpriced_days' => $unpricedDays] : []),
+            ...($daysWithoutValuation ? ['days_without_valuation' => $daysWithoutValuation] : []),
         ]);
 
         return true;
diff --git a/tests/Feature/OpenBanking/BinanceBalanceSyncTest.php b/tests/Feature/OpenBanking/BinanceBalanceSyncTest.php
index 79d70aca..9e8b0d05 100644
--- a/tests/Feature/OpenBanking/BinanceBalanceSyncTest.php
+++ b/tests/Feature/OpenBanking/BinanceBalanceSyncTest.php
@@ -309,6 +309,7 @@ test('first sync fetches historical snapshots and converts using currency API',
                         'balances' => [
                             ['asset' => 'BTC', 'free' => '2.0', 'locked' => '0.0'],
                         ],
+                        'totalAssetOfBtc' => '2.0',
                     ],
                 ],
                 [
@@ -318,6 +319,7 @@ test('first sync fetches historical snapshots and converts using currency API',
                         'balances' => [
                             ['asset' => 'BTC', 'free' => '2.0', 'locked' => '0.0'],
                         ],
+                        'totalAssetOfBtc' => '2.0',
                     ],
                 ],
             ],
@@ -389,6 +391,7 @@ test('subsequent sync only fetches snapshots since last balance date', function
                         'balances' => [
                             ['asset' => 'BTC', 'free' => '1.0', 'locked' => '0.0'],
                         ],
+                        'totalAssetOfBtc' => '1.0',
                     ],
                 ],
             ],
@@ -425,7 +428,7 @@ test('subsequent sync only fetches snapshots since last balance date', function
     expect($todayBalance->balance)->toBe(5600000);
 });
 
-test('historical sync converts assets using currency API', function () {
+test('historical sync values a holding the rate provider cannot price', function () {
     $user = User::factory()->onboarded()->create(['currency_code' => 'EUR']);
     $connection = BankingConnection::factory()->binance()->create([
         'user_id' => $user->id,
@@ -451,13 +454,16 @@ test('historical sync converts assets using currency API', function () {
                         'balances' => [
                             ['asset' => 'SOL', 'free' => '10.0', 'locked' => '0.0'],
                         ],
+                        'totalAssetOfBtc' => '0.02',
                     ],
                 ],
             ],
         ]),
+        // Deliberately no `sol` rate: the provider carries fiat and a couple of
+        // majors, which is why re-pricing each holding dropped everything else.
         'cdn.jsdelivr.net/*currencies/eur*' => Http::response([
             'eur' => [
-                'sol' => 0.01, // 1 EUR = 0.01 SOL → 1 SOL = 100 EUR
+                'btc' => 0.00002, // 1 EUR = 0.00002 BTC → 0.02 BTC = 1000 EUR
             ],
         ]),
         'api.binance.com/api/v3/account*' => Http::response([
@@ -475,7 +481,8 @@ test('historical sync converts assets using currency API', function () {
     $service = app(BinanceBalanceSyncService::class);
     $service->sync($account, $client, isFirstSync: true);
 
-    // Historical: 10 SOL / 0.01 = 1000 EUR → 100000 cents
+    // Binance valued the whole account at 0.02 BTC that day → 1000 EUR.
+    // Re-pricing the SOL ourselves would have found no rate and written zero.
     $yesterdayBalance = $account->balances()->where('balance_date', $yesterday->toDateString())->first();
     expect($yesterdayBalance->balance)->toBe(100000);
 });