Almost three-quarters of participants in a recent Federal Reserve survey said they were "unlikely or very unlikely" to pay with their mobile phone when making retail purchases if given the opportunity, raising questions about a trend that grew threefold between 2011 and 2013.

The reluctance reflects growing scepticism about mobile banking and payment services among some US citizens, even as the technology is rapidly expanding, the results of the Fed's third annual Survey of Consumers' Use of