diff --git a/src/allmende_payment_system/models.py b/src/allmende_payment_system/models.py
index 8c52bf5..3926a84 100644
--- a/src/allmende_payment_system/models.py
+++ b/src/allmende_payment_system/models.py
@@ -234,7 +234,7 @@ class Transaction(Base):
     type: Mapped[TransactionTypes] = mapped_column(nullable=False)
     quantity: Mapped[decimal.Decimal] = mapped_column(Numeric(10, 2), nullable=True)
     timestamp: Mapped[datetime.datetime] = mapped_column(
-        nullable=False, default=datetime.datetime.now()
+        nullable=False, default=datetime.datetime.now
     )
     total_amount: Mapped[decimal.Decimal] = mapped_column(
         Numeric(10, 2), nullable=False