Profitability is critical to the survival of Nigerian deposit money banks which is consistently been eroded by the impaired risk assets. Hence, this study was conducted to examine influence of risk assets impairment on performance of Nigerian deposit money banks. The specific objectives of the study were to; (i) determine the effect of impairment loss on operating profit; (ii) analyze effect non-performing loans ratio affect return on assets of Nigerian deposit money banks. Secondary data were collected and analysed using fixed and random effect regression analysis methods from a sample of 14 listed Nigerian deposit money banks. The study revealed that impairment loss, have significant negative relationship with operating profit (β=2.294, p‹ 0.01) and non-performing loan ratio have significant positive relationship with return on assets (β=0.067, p‹ 0.1). However, other variables such as inflation, liquidity and gross domestic product per capital also have effect on banks performance. The study concluded that risk assets impairment has significant negative influence on performance and that inflation, liquidity and gross domestic product have negative impact on profitability, while bank size has positive impact on profitability. The study recommended that; bank directors should put effective risk assets impairment test in place to boost reported profitability; the bank management should ensure effective management of liquidity ratio to boost return on equity; government policymakers should ensure that banks are mandated to disclose their risk assets impairment and expand their size by extending banking services to the unbanked areas.

Cost efficiency is very important in this new age since profitability continue to shrink and new business is becoming almost impossible. Therefore, this study is to examine impact of cost efficiency on financial performance of Nigeria deposit money banks. The specific objectives of the study were to; (i) test the effects of efficiency in Fueling and maintenance costs on the performance of Nigerian deposit money banks; (ii) to examine the impact of efficiency in General Administrative expenses on the Performance of Nigerian deposit money banks. Secondary data were collected from annual financial statements of the selected banks. Fixed-effect and random-effect regression analysis method were used to analyze the data from a sample of 13 listed Nigerian deposit money banks covering period of 2010 to 2019. The results showed that cost efficiency have significant impact on financial performance of Nigerian deposit money banks. Implying that bank managements tend to increase profitability by increasing power-running cost efficiency, and by reducing general administrative cost efficiency. The study recommends that; Bank management need to tap into alternative source of energy and holistic approach to monitor wastages and theft of fuel to reduce power running cost for performance increasement. The board of directors should ensure that good business administration is their focus, by employing efficient control on administrative expenses to improve bank performance.