MarketingVOX: Nearly half - 48 percent - of online retailers say their chargebacks for fraudulent purchase transactions constitute less than 0.1 percent of sales, matching the credit card chargeback rate of physical stores, the Merchant Risk Council reports in its Fifth Annual Survey, reports Internet Retailer. Still, fraud remains a challenge, with one-third of retailers experiencing a fraud spike in the previous 12 months that double their fraud rate, the study says.