Nigeria’s banking industry may have several commercial lenders, but more than half of its financial firepower is concentrated in just five institutions.
Access Bank, FirstBank, Guaranty Trust Bank, United Bank for Africa and Zenith Bank collectively held about ₦94.87 trillion in assets at the end of 2025, representing 57.19% of total banking-sector assets, according to Central Bank of Nigeria data reported by BusinessDay.
The concentration goes beyond assets. The five systemically important banks also account for a large share of customer deposits and industry lending, making their stability critical to Nigeria’s financial system.
That is why the CBN subjects them to closer supervision. A problem at a small lender may affect its customers. A serious problem at one of these five could have consequences across payments, businesses, lending and the wider economy.
Here are the five banks at the centre of Nigeria’s banking system.
1. Access Bank
Access Bank has grown from a relatively modest Nigerian lender into one of Africa’s largest banking groups through a combination of acquisitions and international expansion.
Its scale gives it significant exposure to corporate banking, retail customers, payments and cross-border business across several African markets.
Access has also been one of the most aggressive Nigerian banks in acquisition-led expansion, helping the group build a much broader geographic footprint than many domestic competitors.
For the CBN, size creates another issue: the bigger a bank becomes, the greater the potential effect of a failure on other parts of the financial system.
That makes Access Bank one of the institutions whose capital, liquidity, governance and risk exposure regulators must watch particularly closely.
2. FirstBank
FirstBank sits at the centre of one of Nigeria’s oldest financial institutions.
Its importance comes from more than history. The bank has a huge customer base, substantial deposits and a large balance sheet spanning retail, corporate and commercial banking.
Its parent, First HoldCo, has also undergone a major transformation as the group works through legacy asset-quality problems and strengthens capital.
The ownership structure has become another point of attention following Femi Otedola’s rapid accumulation of First HoldCo shares.
But from a systemic perspective, FirstBank matters because of the sheer volume of businesses and individuals connected to it.
A bank of that scale cannot be treated like an ordinary financial institution.
3. Guaranty Trust Bank
Guaranty Trust Bank has historically pursued a somewhat different model from some of its larger rivals.
Rather than relying primarily on an enormous physical branch network, GTBank built a reputation around efficiency, digital banking and high returns.
It now operates under Guaranty Trust Holding Company, or GTCO, which gives the wider group exposure to other financial-services businesses.
GTBank’s importance to the sector comes not only from asset size but also from its position in corporate banking, consumer payments and digital transactions.
That combination makes its operational resilience particularly important as more Nigerian banking activity moves online.
4. United Bank for Africa
UBA has developed one of the broadest African footprints of any Nigerian bank.
Its operations span numerous African countries alongside international offices, giving it exposure to cross-border payments, trade finance and multinational corporate business.
That geographic reach differentiates UBA from banks whose balance sheets are more heavily concentrated in Nigeria.
It can also create additional complexity.
A pan-African bank must manage different currencies, regulatory regimes, political environments and economic cycles while protecting the stability of its Nigerian operations.
That makes UBA strategically important both domestically and across Africa.
5. Zenith Bank
Zenith Bank remains one of Nigeria’s dominant corporate lenders and one of the country’s largest banks by balance-sheet size.
Its strength has historically come from corporate banking, large deposits and relationships with major Nigerian businesses.
Alongside Access, FirstBank, GTBank and UBA, Zenith forms part of the core group the CBN considers systemically important.
The designation essentially recognises that some institutions are so deeply connected to the financial system that regulators cannot assess their risks in isolation.
Do Five Banks Have Too Much Power?
The fact that five institutions hold 57.19% of banking assets does not mean they control Nigeria’s banking industry or the CBN.
It means the market is concentrated.
That concentration brings advantages.
Large banks can finance bigger transactions, invest more heavily in technology, absorb economic shocks and support infrastructure or corporate projects smaller institutions may struggle to fund.
Nigeria’s recapitalisation exercise was partly designed to build stronger banks capable of supporting a much larger economy. International commercial banks were required to reach at least ₦500 billion in minimum paid-up capital, while national banks faced a ₦200 billion requirement. The process has substantially strengthened capital across the sector.
But concentration creates risk too.
When a small bank fails, the impact can often be contained.
When an institution holding a significant share of deposits, credit and payment flows develops serious problems, the consequences can spread through the financial system.
That is the logic behind identifying banks as systemically important.
Why Is CBN Watching the Big Five More Closely?
After the recapitalisation drive, the CBN has shifted attention towards governance, risk management and how banks deploy their enlarged capital bases.
CBN officials have argued that a larger balance sheet alone does not make a bank stronger. Governance, risk controls and the quality of assets remain critical.
The regulator has therefore tightened requirements around leadership succession, related-party lending and board accountability as banks enter the post-recapitalisation era.
That oversight matters even more for institutions responsible for more than half of the sector’s assets.
Nigeria may have many banks, but the financial system relies disproportionately on a handful of them.
The CBN’s challenge is therefore balancing two objectives: allowing its largest banks to become strong enough to finance Nigeria’s economy while ensuring none becomes so important that excessive risk threatens the entire system.