Commonwealth Bank of Australia Ltd (CBA) has achieved a large improvement in customer satisfaction ratings at its business bank, but it still lags its three biggest rivals.
A survey by TNS Communications Australia gave CBA's business bank a customer satisfaction rating of 73.9 per cent.
It followed National Australia Bank on 75.7 per cent, Westpac on 80.0 per cent and ANZ on 82.4 per cent.
St George beat all the majors with a rating of 84.3 per cent.
CBA chief executive Ralph Norris has made improving the former state-owned bank's poor customer satisfaction ratings one of his key priorities.
Mr Norris would be pleased by the 13.2 per cent improvement in CBA's ranking in the year to June 30, more than any other bank.
Bank of Queensland scored the best rating at 90.4 per cent, while the average for the all the banks was 80 per cent.
TNS's annual survey was based on a rolling sample of about 9,900 non-agricultural businesses with annual turnover up to $100 million.