diff --git a/src/app/Http/Controllers/API/V4/Admin/WalletsController.php b/src/app/Http/Controllers/API/V4/Admin/WalletsController.php
--- a/src/app/Http/Controllers/API/V4/Admin/WalletsController.php
+++ b/src/app/Http/Controllers/API/V4/Admin/WalletsController.php
@@ -91,7 +91,7 @@
                 'object_id' => $wallet->id,
                 'object_type' => Wallet::class,
                 'type' => $type,
-                'amount' => $amount < 0 ? $amount * -1 : $amount,
+                'amount' => $amount,
                 'description' => $request->description
             ]
         );
diff --git a/src/app/Http/Controllers/API/V4/WalletsController.php b/src/app/Http/Controllers/API/V4/WalletsController.php
--- a/src/app/Http/Controllers/API/V4/WalletsController.php
+++ b/src/app/Http/Controllers/API/V4/WalletsController.php
@@ -246,25 +246,12 @@
         }
 
         $result = $result->map(function ($item) use ($isAdmin) {
-            $amount = $item->amount;
-
-            $negatives = [
-                Transaction::WALLET_CHARGEBACK,
-                Transaction::WALLET_DEBIT,
-                Transaction::WALLET_PENALTY,
-                Transaction::WALLET_REFUND,
-            ];
-
-            if (in_array($item->type, $negatives)) {
-                $amount *= -1;
-            }
-
             $entry = [
                 'id' => $item->id,
                 'createdAt' => $item->created_at->format('Y-m-d H:i'),
                 'type' => $item->type,
                 'description' => $item->shortDescription(),
-                'amount' => $amount,
+                'amount' => $item->amount,
                 'hasDetails' => !empty($item->cnt),
             ];
 
diff --git a/src/app/Providers/PaymentProvider.php b/src/app/Providers/PaymentProvider.php
--- a/src/app/Providers/PaymentProvider.php
+++ b/src/app/Providers/PaymentProvider.php
@@ -185,7 +185,7 @@
                 'object_id' => $wallet->id,
                 'object_type' => Wallet::class,
                 'type' => $transaction_type,
-                'amount' => $refund['amount'],
+                'amount' => $refund['amount'] * -1,
                 'description' => $refund['description'] ?? '',
         ]);
 
diff --git a/src/app/Transaction.php b/src/app/Transaction.php
--- a/src/app/Transaction.php
+++ b/src/app/Transaction.php
@@ -159,6 +159,8 @@
             'description' => $this->{'description'},
         ];
 
+        $amount = $this->amount * ($this->amount < 0 ? -1 : 1);
+
         if ($entitlement = $this->entitlement()) {
             $wallet = $entitlement->wallet;
             $cost = $entitlement->cost;
@@ -172,7 +174,7 @@
         }
 
         $result['wallet'] = $wallet->{'description'} ?: 'Default wallet';
-        $result['amount'] = $wallet->money($this->amount);
+        $result['amount'] = $wallet->money($amount);
 
         return $result;
     }
diff --git a/src/app/Wallet.php b/src/app/Wallet.php
--- a/src/app/Wallet.php
+++ b/src/app/Wallet.php
@@ -254,7 +254,7 @@
                 'object_id' => $this->id,
                 'object_type' => \App\Wallet::class,
                 'type' => \App\Transaction::WALLET_DEBIT,
-                'amount' => $amount
+                'amount' => $amount * -1
             ]
         );
 
diff --git a/src/database/migrations/2021_02_19_100000_transaction_amount_fix.php b/src/database/migrations/2021_02_19_100000_transaction_amount_fix.php
new file mode 100644
--- /dev/null
+++ b/src/database/migrations/2021_02_19_100000_transaction_amount_fix.php
@@ -0,0 +1,38 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+// phpcs:ignore
+class TransactionAmountFix extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        $negatives = [
+            \App\Transaction::WALLET_CHARGEBACK,
+            \App\Transaction::WALLET_DEBIT,
+            \App\Transaction::WALLET_PENALTY,
+            \App\Transaction::WALLET_REFUND,
+        ];
+
+        $query = "UPDATE transactions SET amount = amount * -1"
+            . " WHERE type IN (" . implode(',', array_fill(0, count($negatives), '?')) . ")";
+
+        DB::select($query, $negatives);
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        DB::select("UPDATE transactions SET amount = amount * -1 WHERE amount < 0");
+    }
+}
diff --git a/src/tests/Feature/Controller/Admin/WalletsTest.php b/src/tests/Feature/Controller/Admin/WalletsTest.php
--- a/src/tests/Feature/Controller/Admin/WalletsTest.php
+++ b/src/tests/Feature/Controller/Admin/WalletsTest.php
@@ -133,7 +133,7 @@
             ->where('type', Transaction::WALLET_PENALTY)->first();
 
         $this->assertSame($post['description'], $transaction->description);
-        $this->assertSame(4000, $transaction->amount);
+        $this->assertSame(-4000, $transaction->amount);
         $this->assertSame($admin->email, $transaction->user_email);
     }
 
diff --git a/src/tests/Feature/Controller/PaymentsMollieTest.php b/src/tests/Feature/Controller/PaymentsMollieTest.php
--- a/src/tests/Feature/Controller/PaymentsMollieTest.php
+++ b/src/tests/Feature/Controller/PaymentsMollieTest.php
@@ -717,7 +717,7 @@
         $transactions = $wallet->transactions()->where('type', Transaction::WALLET_REFUND)->get();
 
         $this->assertCount(1, $transactions);
-        $this->assertSame(101, $transactions[0]->amount);
+        $this->assertSame(-101, $transactions[0]->amount);
         $this->assertSame(Transaction::WALLET_REFUND, $transactions[0]->type);
         $this->assertSame("refund desc", $transactions[0]->description);
 
@@ -774,7 +774,7 @@
         $transactions = $wallet->transactions()->where('type', Transaction::WALLET_CHARGEBACK)->get();
 
         $this->assertCount(1, $transactions);
-        $this->assertSame(15, $transactions[0]->amount);
+        $this->assertSame(-15, $transactions[0]->amount);
         $this->assertSame(Transaction::WALLET_CHARGEBACK, $transactions[0]->type);
         $this->assertSame('', $transactions[0]->description);
 
diff --git a/src/tests/TestCaseTrait.php b/src/tests/TestCaseTrait.php
--- a/src/tests/TestCaseTrait.php
+++ b/src/tests/TestCaseTrait.php
@@ -80,7 +80,7 @@
                 'object_id' => $wallet->id,
                 'object_type' => \App\Wallet::class,
                 'type' => Transaction::WALLET_DEBIT,
-                'amount' => $debit,
+                'amount' => $debit * -1,
                 'description' => 'Payment',
         ]);
         $result[] = $transaction;
@@ -107,12 +107,13 @@
         // The page size is 10, so we generate so many to have at least two pages
         $loops = 10;
         while ($loops-- > 0) {
+            $type = $types[count($result) % count($types)];
             $transaction = Transaction::create([
                 'user_email' => 'jeroen.@jeroen.jeroen',
                 'object_id' => $wallet->id,
                 'object_type' => \App\Wallet::class,
-                'type' => $types[count($result) % count($types)],
-                'amount' => 11 * (count($result) + 1),
+                'type' => $type,
+                'amount' => 11 * (count($result) + 1) * ($type == Transaction::WALLET_PENALTY ? -1 : 1),
                 'description' => 'TRANS' . $loops,
             ]);
             $transaction->created_at = $date->next(Carbon::MONDAY);
diff --git a/src/tests/Unit/TransactionTest.php b/src/tests/Unit/TransactionTest.php
--- a/src/tests/Unit/TransactionTest.php
+++ b/src/tests/Unit/TransactionTest.php
@@ -26,7 +26,7 @@
                 'object_id' => $wallet->id,
                 'object_type' => Wallet::class,
                 'type' => Transaction::WALLET_PENALTY,
-                'amount' => 9,
+                'amount' => -10,
                 'description' => "A test penalty"
         ]);
 
@@ -34,7 +34,7 @@
                 'object_id' => $wallet->id,
                 'object_type' => Wallet::class,
                 'type' => Transaction::WALLET_DEBIT,
-                'amount' => 10
+                'amount' => -9
         ]);
 
         $transaction = Transaction::create([
@@ -84,10 +84,10 @@
 
         $transactions = Transaction::where('amount', '<', 20)->orderBy('amount')->get();
 
-        $this->assertSame(9, $transactions[0]->amount);
+        $this->assertSame(-10, $transactions[0]->amount);
         $this->assertSame(Transaction::WALLET_PENALTY, $transactions[0]->type);
         $this->assertSame(
-            "The balance of Default wallet was reduced by 0,09 CHF; A test penalty",
+            "The balance of Default wallet was reduced by 0,10 CHF; A test penalty",
             $transactions[0]->toString()
         );
         $this->assertSame(
@@ -95,10 +95,10 @@
             $transactions[0]->shortDescription()
         );
 
-        $this->assertSame(10, $transactions[1]->amount);
+        $this->assertSame(-9, $transactions[1]->amount);
         $this->assertSame(Transaction::WALLET_DEBIT, $transactions[1]->type);
         $this->assertSame(
-            "0,10 CHF was deducted from the balance of Default wallet",
+            "0,09 CHF was deducted from the balance of Default wallet",
             $transactions[1]->toString()
         );
         $this->assertSame(