Commonwealth Bank subsidiary Bankwest has the dubious distinction of appearing in several product categories with above-average dispute levels in the Financial Ombudsman Service's 2014/15 dispute league table.Rather than publish the raw number of disputes for each financial institution, FOS provides a measure called "chance of a dispute coming to FOS", which shows the number of disputes relative to the size of the business.For example, the likelihood that a home loan borrower will take a dispute with their lender to the Financial Ombudsman Service is 40.8 in 100,000. That is, FOS's complaints file for 2014/15 shows that for every 100,000 home loan customers the median number of disputes was 40.8.Home lending attracts a high proportion of complaints to FOS. Compared with the median of 40.8, Bank of Queensland had the worst rating in the category, at 89.8. Other lenders whose chance of dispute was above the median included Rams Financial Group, at 67.8, and Bankwest, at 72.2. Among the big banks, ANZ's rating was 44.8, Commonwealth Bank's 40.3, National Australia Bank's 43.2 and Westpac's 22.The lender with the lowest chance of dispute was Citibank, with a rating of 12.2.Another area that attracts a lot of disputes is credit cards. Compared with the median chance of a dispute of 23.4, Lion Finance had the worst rating in the category, at 50.3.Other credit card issuers whose chance of a dispute was above the median included Bank of Melbourne, at 34.5, and Bankwest, at 34.2.The card issuer with the lowest chance of dispute was BankSA, with a rating of 6.8.The consumer lending category threw up some big numbers. Compared with the median chance of a dispute of 68.5, St George Motor Finance had a rating of 497.1. That means that almost one in every 200 customers ended up in dispute.Other consumer lenders whose chance of a dispute was well above the median included HSBC Bank Australia, at 111.4, Bankwest, at 105.6 and GE Automotive Financial Services, at 105.2.