diff --git a/src/EventListener/AccountingTransactionsListener.php b/src/EventListener/AccountingTransactionsListener.php
new file mode 100644
index 0000000..48c309c
--- /dev/null
+++ b/src/EventListener/AccountingTransactionsListener.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace App\EventListener;
+
+use App\Entity\AccountingTransaction;
+use Doctrine\Bundle\DoctrineBundle\Attribute\AsEntityListener;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\Event\PostPersistEventArgs;
+use Doctrine\ORM\Events;
+
+#[AsEntityListener(event: Events::postPersist, method: 'postPersist', entity: AccountingTransaction::class)]
+final class AccountingTransactionsListener
+{
+    public function __construct(
+        private EntityManagerInterface $entityManager
+    ) {}
+
+    public function postPersist(
+        AccountingTransaction $transaction,
+        PostPersistEventArgs $event
+    ) {
+        $origin = $transaction->getOrigin();
+        $origin->addTransactionsIssued($transaction);
+
+        $this->entityManager->persist($origin);
+
+        $target = $transaction->getTarget();
+        $target->addTransactionsReceived($transaction);
+
+        $this->entityManager->persist($target);
+
+        $this->entityManager->flush();
+    }
+}
diff --git a/tests/Entity/AccountingTest.php b/tests/Entity/AccountingTest.php
index df69e3b..29fde8c 100644
--- a/tests/Entity/AccountingTest.php
+++ b/tests/Entity/AccountingTest.php
@@ -3,6 +3,8 @@
 namespace App\Tests\Entity;
 
 use App\Entity\Accounting;
+use App\Entity\AccountingTransaction;
+use App\Entity\Money;
 use App\Entity\Tipjar;
 use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
@@ -59,4 +61,49 @@ class AccountingTest extends KernelTestCase
         $this->assertEquals(Tipjar::class, $accountingB->getOwnerClass());
         $this->assertEquals('TEST_TIPJAR_B', $accountingB->getTipjar()->getName());
     }
+
+    public function testAccountingGetsUpdatedByTransactions()
+    {
+        $tipjarA = new Tipjar();
+        $tipjarA->setName('TEST_TIPJAR_A');
+
+        $accountingA = new Accounting();
+        $accountingA->setTipjar($tipjarA);
+
+        $tipjarB = new Tipjar();
+        $tipjarB->setName('TEST_TIPJAR_B');
+
+        $accountingB = new Accounting();
+        $accountingB->setTipjar($tipjarB);
+
+        $transaction = new AccountingTransaction();
+        $transaction->setMoney(new Money(120, 'EUR'));
+        $transaction->setOrigin($accountingA);
+        $transaction->setTarget($accountingB);
+
+        $this->entityManager->persist($transaction);
+        $this->entityManager->flush();
+
+        $accountingA = $this->entityManager
+            ->getRepository(Tipjar::class)
+            ->findOneBy(['name' => 'TEST_TIPJAR_A'])
+            ->getAccounting();
+
+        $accountingB = $this->entityManager
+            ->getRepository(Tipjar::class)
+            ->findOneBy(['name' => 'TEST_TIPJAR_B'])
+            ->getAccounting();
+
+        $this->assertCount(1, $accountingA->getTransactionsIssued());
+        $this->assertCount(0, $accountingA->getTransactionsReceived());
+
+        $this->assertCount(0, $accountingB->getTransactionsIssued());
+        $this->assertCount(1, $accountingB->getTransactionsReceived());
+
+        $this->assertEquals(120, $accountingA->getTransactionsIssued()[0]->getMoney()->amount);
+        $this->assertEquals('EUR', $accountingA->getTransactionsIssued()[0]->getMoney()->currency);
+
+        $this->assertEquals(120, $accountingB->getTransactionsReceived()[0]->getMoney()->amount);
+        $this->assertEquals('EUR', $accountingB->getTransactionsReceived()[0]->getMoney()->currency);
+    }
 }