diff --git a/ChangeLog b/ChangeLog
index 2c18ef5a5..ff4b6d713 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jan  4 11:55:41 CET 2018
+	Fix issue #5234 (aggregator ignoring refunds).
+	Misc. minor fixes to the auditor. -CG
+
 Mon Jan  1 23:15:37 CET 2018
 	Add TALER_EXCHANGE_refund2() API call to libtalerexchange. -CG
 
diff --git a/src/exchange/taler-exchange-aggregator.c b/src/exchange/taler-exchange-aggregator.c
index c9ff958f0..d5d43052d 100644
--- a/src/exchange/taler-exchange-aggregator.c
+++ b/src/exchange/taler-exchange-aggregator.c
@@ -123,6 +123,11 @@ struct AggregationUnit
    */
   struct GNUNET_HashCode h_wire;
 
+  /**
+   * Hash code of contract we are currently looking into.
+   */
+  const struct GNUNET_HashCode *h_contract;
+
   /**
    * Wire transfer identifier we use.
    */
@@ -568,6 +573,53 @@ exchange_serve_process_config ()
 }
 
 
+/**
+ * Callback invoked with information about refunds applicable
+ * to a particular coin.  Subtract refunded amount(s) from
+ * the aggregation unit's total amount.
+ *
+ * @param cls closure with a `struct AggregationUnit *`
+ * @param merchant_pub public key of merchant who authorized refund
+ * @param merchant_sig signature of merchant authorizing refund
+ * @param h_contract hash of contract being refunded
+ * @param rtransaction_id refund transaction ID
+ * @param amount_with_fee amount being refunded
+ * @param refund_fee fee the exchange keeps for the refund processing
+ * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
+ */
+static int
+refund_by_coin_cb (void *cls,
+		   const struct TALER_MerchantPublicKeyP *merchant_pub,
+		   const struct TALER_MerchantSignatureP *merchant_sig,
+		   const struct GNUNET_HashCode *h_contract,
+		   uint64_t rtransaction_id,
+		   const struct TALER_Amount *amount_with_fee,
+		   const struct TALER_Amount *refund_fee)
+{
+  struct AggregationUnit *au = cls;
+
+  /* TODO: potential optimization: include these conditions
+     in the SELECT! */
+  if (0 != memcmp (merchant_pub,
+		   &au->merchant_pub,
+		   sizeof (struct TALER_MerchantPublicKeyP)))
+    return GNUNET_OK; /* different merchant */
+  if (0 != memcmp (h_contract,
+		   au->h_contract,
+		   sizeof (struct GNUNET_HashCode)))
+    return GNUNET_OK; /* different contract */
+  if (GNUNET_OK !=
+      TALER_amount_subtract (&au->total_amount,
+			     &au->total_amount,
+			     amount_with_fee))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+						
+
 /**
  * Function called with details about deposits that have been made,
  * with the goal of executing the corresponding wire transaction.
@@ -610,6 +662,20 @@ deposit_cb (void *cls,
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   au->row_id = row_id;
+
+  au->h_contract = h_contract_terms;
+  qs = db_plugin->select_refunds_by_coin (db_plugin->cls,
+					  au->session,
+					  coin_pub,
+					  &refund_by_coin_cb,
+					  au);
+  au->h_contract = NULL;
+  if (0 > qs)
+  {
+    GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
+    return qs;
+  }
+  
   GNUNET_assert (NULL == au->wire);
   au->wire = json_incref ((json_t *) wire);
   if (GNUNET_OK !=
@@ -731,6 +797,20 @@ aggregate_cb (void *cls,
     /* Skip this one, but keep going! */
     return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
   }
+
+  au->h_contract = h_contract_terms;
+  qs = db_plugin->select_refunds_by_coin (db_plugin->cls,
+					  au->session,
+					  coin_pub,
+					  &refund_by_coin_cb,
+					  au);
+  au->h_contract = NULL;
+  if (0 > qs)
+  {
+    GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
+    return qs;
+  }
+  
   if (au->rows_offset >= aggregation_limit)
   {
     /* Bug: we asked for at most #aggregation_limit results! */