diff --git a/datanode/api/trading_data_v2.go b/datanode/api/trading_data_v2.go
index ffced3435d..f384b7c63a 100644
--- a/datanode/api/trading_data_v2.go
+++ b/datanode/api/trading_data_v2.go
@@ -3889,6 +3889,10 @@ func calcPositionMarginCappedAndFullyCollateralised(
 		ongoing = ongoing.Add(v.Price.Mul(num.DecimalFromInt64(size)))
 	}
 
+	// no volume, and we want to prevent division by 0
+	if totalVolume == 0 {
+		return num.DecimalZero()
+	}
 	averageEntryPrice := ongoing.Div(num.DecimalFromInt64(totalVolume))
 
 	if positionSize < 0 {