diff --git a/app/modules/expense/db.py b/app/modules/expense/db.py
index f1f4424..da9896a 100644
--- a/app/modules/expense/db.py
+++ b/app/modules/expense/db.py
@@ -465,7 +465,7 @@ class ExpenseDBStore:
         out = dict(row)
         if isinstance(out.get("spent_at"), date):
             out["spent_at"] = out["spent_at"].isoformat()
-        for k in ("created_at", "updated_at"):
+        for k in ("created_at", "updated_at", "decided_at"):
             v = out.get(k)
             if isinstance(v, datetime):
                 out[k] = v.astimezone(timezone.utc).isoformat(timespec="seconds")