Charge cards are back as the dominant product for American Express in Australia, thanks to a one third decline in the size of the firm's credit card balances over 2011.Financial statements for American Express Australia, filed with ASIC, show credit card balances were A$1.63 billion at the end of last year, down from $2.47 billion at the end of 2010.Charge card receivables increased five per cent to $1.95 billion over the year.The changing business mix may reflect the steady gains in the firm's list of corporate customers, on the one hand, and the shift in consumer demand for credit on the other.The latter may of most interest given the high-income skew of the financier's customer base in Australia.Reserve Bank of Australia data on credit card receivables shows a rise of two per cent in the level of credit card balances over 2011. This is the lowest level of growth (on a calendar year basis) since the RBA began to compile data in the mid-1980s. While receivables are down, the incidence of delinquencies is up in the credit card book. Loans 30 days or more past due were 9.5 per cent at the end of 2011, up from 7.6 per cent at the end of 2010.Delinquencies decreased in the charge card book to 7.2 per cent at the end of 2011, from 7.8 per cent at the end of 2010.American Express cut the charge for bad debts in 2011 to $77 million, one third lower than in 2010.Profit for the group remains slight, at $8.2 million for 2011, but is up from $2.0 million in 2010. The return on assets is less than 0.2 per cent and the return on equity less than five per cent.One bright spot is that the subsidy to David Jones for the retail chain's co-branded credit card will finish next year. American Express had been handing over most of the profit of the co-brand to its department store partner.