The recent launch of Apple Pay in Australia, exclusively for American Express issued credit card holders, represents a good strategic fit, according to a Roy Morgan survey aimed at testing how many Amex cardholders were also iPhone owners.The poll of 50,000 people found that over half (52 per cent) of Amex credit card holders (non-bank issued) have an iPhone, well ahead of Mastercard holders (36 per cent) and Visa (35 per cent) and similar to the ownership levels reported among the Big Four banks' customers (about 35 per cent). Amex cardholders also have the highest spend on credit cards overall, well ahead of their major card competitors. Extrapolating these findings, Roy Morgan calculated that, with 221,000 holders of Amex-issued credit cards in Australia owning iPhones and spending an average of A$4,560 across all their credit cards each month, the potential turnover for Apple Pay might one day reach $1 billion per month.At this stage, though, the number of Amex card-holders who own an iPhone 6, the only model capable of accessing Apple Pay, sits at just over 80,000, and not all their card spend is via Amex. "At present, Amex is only gaining 43 per cent of their customers' card spend … so the full potential of business likely to be conducted on Apple Pay will depend on Amex achieving a greater share of their [cardholders'] spend," said Norman Morris, industry communications director at Roy Morgan Research.