In its 2018 survey of the Top 1000 commercial banks in the world, The Banker magazine included nine banks operating in Nigeria on the list, with five banks ranked among the top 25 banks in Africa. The rankings are based on the banks' Tier One capital at end-2017, as defined by the Basel Bank of International Settlements. The aggregate Tier One capital of Nigerian banks totaled $9.6bn at the end of 2017 relative to about $8.9bn a year earlier, and accounted for 12.7% of the Tier One capital of banks in Africa. Also, the aggregate assets of the nine banks reached $93.1bn at the end of 2017 and accounted for 9.9% of the aggregate assets of banks in Africa. As such, Nigerian banks' combined Tier One capital-to-assets ratio was 10.4% at end-2017, higher than the ratio of 8.05% of banks in Africa and the Top 1000 banks' aggregate ratio of 6.7%. Also, the cumulative pre-tax profits of the nine banks reached $2.4bn in 2017. The ratio of pre-tax profits-to-Tier One capital of Nigerian banks reached 25% in 2017, higher than the Top 1000 banks' ratio of 13.5%. The Tier One capital of Zenith Bank was $2.47bn in 2017, the highest among Nigerian banks, followed by Guarantee Trust Bank ($1.51bn), First Bank of Nigeria ($1.45bn), Access Bank ($1.3bn), United Bank for Africa ($711m), Ecobank Nigeria ($603m), Stanbic IBTC Holdings ($556m), Diamond Bank ($553m) and Fidelity Bank ($491m).  
Source: The Banker