The number of merchants applying a surcharge to customer card payments is increasing but the surcharge rate is steady, according to industry analyst East & Partners.The number of merchants applying a surcharge increased from 24.5 percent of survey respondents at the end of 2010 to 41.7 per cent in December 2013.East & Partners' head of markets analysis, Lachlan Colquhoun, said the average surcharge rate at the end of last year was 2.1 per cent - unchanged from the previous survey in June last year.Under rules introduced by the Reserve Bank last year, merchants have a right to recover their card acceptance costs through a surcharge. The "reasonable cost of acceptance" includes the merchant service fee, charged by the merchant's acquiring bank, and some additional costs.Card scheme operators have the right to change their scheme rules to limit surcharging to reasonable cost.Colquhoun said the RBA's surcharging rules were having an impact, with fewer merchants saying they planned to increase their rates."The reforms seem to be having an impact in terms of making businesses think twice before increasing surcharge levels, but we are not seeing much evidence that they are inclined to take them lower," he said.Large companies are much more inclined to apply surcharges than small companies. East & Partners found that 65 per cent of institutional businesses (with turnover of A$725 million or more) applied a surcharge, while only 32.8 per cent of micro-businesses (with turnover of $1 million to $5 million a year) applied a surcharge.Over the past six months institutional businesses dropped their average surcharge rate from 2.3 per cent to 2.1 per cent. Micro-businesses increased their average rate from two per cent to 2.2 per cent.