High-income earners are fussy when it comes to rating the performance of their banks. While overall customer satisfaction with the big banks is at its highest level for almost 20 years, the ratings that prized high net worth customers give their banks are much lower.According to Roy Morgan Research, last month 81.1 per cent of Commonwealth Bank customers said they were satisfied with their bank, while only 73.7 per cent of customers who earn more than A$100,000 said they were satisfied.In National Australia Bank's case, the overall satisfaction rating was 79.1 per cent, compared with 74.3 per cent for customers earning more than $100,000.In ANZ's case, the overall rating was 78 per cent, and the rating from high-income earners was 69 per cent.Westpac's ratings were a little different. Its overall satisfaction rating was 78.7 per cent and its satisfaction rating among high-income earners was 78.1 per cent.Roy Morgan said customers earning less than $35,000 a year give their banks the highest ratings. The good news is that this group makes up 54 per cent of the population; the bad news is that it accounts for only 27.8 per cent of the value of the market for financial services.Roy Morgan's industry communications director, Norman Morris, said: "The banks will need to increase their focus on the group with the greatest profit potential. They are likely to face increased competition from specialist banks and other financial institutions that will cherry pick high value customers."