ExecutionReport averagePriceReport = (ExecutionReport) averagePriceReportHolder.getReport(); BigDecimal existingCumQty = averagePriceReport.getCumulativeQuantity(); BigDecimal existingAvgPx = averagePriceReport.getAveragePrice(); BigDecimal newLastQty = lastQuantity; BigDecimal newTotal = existingCumQty.add(newLastQty);