The US Afterpay rollout "is performing well with strong conversion and basket size dynamics similar to our experience in Australia," Afterpay Touch told the ASX on Friday."The debit/credit card mix is sitting at levels similar to Australia," Afterpay said.As for lending losses, there is no elaboration on the US experience in the statement, but the financier is bracing for trouble."While the US business is still at an early stage and transaction data is limited (albeit in line with early expectations), Afterpay will implement additional risk and transaction control measures progressively, and in response to future results and observed dynamics specifically relevant to the US market," - for which read 'fraud'.Cotton On is maybe the best known brand listed as "now present on our US platform', of which 14 are featured in Friday's announcement.In the US, "Afterpay in-store is building momentum. Approximately 10,000 individual shopfronts are now live with Afterpay in-store," the company said."Gross losses and net transaction losses trended down" over the June 2018 quarter, it said.These "generally improved" over June 2018 half, "despite the increased underlying sales performance and merchant diversification in the same period. Consequently, a stronger net transaction margin is expected."Afterpay Touch Group bragged on Friday that "over A$2.2 billion of total underlying sales [was] processed through the Afterpay platform over the year to June 2018," a 289 per cent increase over one year.In addition, the June 2018 quarter "underlying sales of approximately A$736 million represents a 171 per cent increase over 2017, and a 39 per cent increase" over the March 2018 quarter.The company said approximately 16,500 retailers and approximately 2.2 million customers were currently live and had transacted on the Afterpay platform since inception.