Credit card fees, bank changes and mortgage interest rates will all be under the microscope as part of a Commerce Commission investigation into the banking sector. The government's ordered the market study that will take more than a year. It follows what it describes as consistently high profits among the top four NZ banks, that are all Australian owned and hold close to 85 percent of mortgage and other lending and a 90 percent share of total bank deposits. Last year NZ banks made a net profit of more than $7 billion, about 17 percent higher than the previous year. Minister for Commerce and Consumer Affairs, Duncan Webb explained to Lisa Owen why an in-depth investigation is needed. [embed] https://players.brightcove.net/6093072280001/default_default/index.html?videoId=6329774497112