diff --git a/src/dexorder/event_handler.py b/src/dexorder/event_handler.py
index 05e8af0..94a968f 100644
--- a/src/dexorder/event_handler.py
+++ b/src/dexorder/event_handler.py
@@ -84,7 +84,8 @@ async def handle_swap_filled(event: EventData):
         log.warning(f'DexorderSwapFilled IGNORED due to missing order {vault} {order_index}')
         return
     value = await accounting_fill(event, order.order.tokenOut)
-    metric.volume.inc(float(value))
+    if value is not None:
+        metric.volume.inc(float(value))
     order.status.trancheStatus[tranche_index].activationTime = next_execution_time  # update rate limit
     try:
         triggers = OrderTriggers.instances[order.key]