diff --git a/app/apps/transactions/templatetags/currency_display.py b/app/apps/transactions/templatetags/currency_display.py
index 20d05d1..43106e6 100644
--- a/app/apps/transactions/templatetags/currency_display.py
+++ b/app/apps/transactions/templatetags/currency_display.py
@@ -1,3 +1,5 @@
+from decimal import Decimal
+
 from django import template
 from django.utils.formats import number_format
 
@@ -6,13 +8,16 @@ register = template.Library()
 
 
 def _format_string(prefix, amount, decimal_places, suffix):
-    formatted_amount = number_format(
-        value=abs(amount), decimal_pos=decimal_places, force_grouping=True
-    )
-    if amount < 0:
-        return f"-{prefix}{formatted_amount}{suffix}"
+    if isinstance(amount, (int, float, Decimal)):
+        formatted_amount = number_format(
+            value=abs(amount), decimal_pos=decimal_places, force_grouping=True
+        )
+        if amount < 0:
+            return f"-{prefix}{formatted_amount}{suffix}"
+        else:
+            return f"{prefix}{formatted_amount}{suffix}"
     else:
-        return f"{prefix}{formatted_amount}{suffix}"
+        return "ERR"
 
 
 @register.simple_tag(name="currency_display")