Indeed, net interest income and income from fees and commissions have been either decreasing or showing a sluggish growth and thus the core profitability in the banking sector has not necessarily improved. The Bank of Japan releases the Financial System Report biannually, presenting a comprehensive analysis of Japan's financial system.
The latest edition released in September this year analyzed the long-term profitability of the overall banking sector (i.e. the major, the regional and the shinkin banks) since the early 1980s, and the following results came up.