The "Big 4 banks" refer to the four largest banks in a particular country known for dominating the banking sector in terms of size, assets, market influence, and services offered.
In the United States:
The Big 4 banks are:
- JPMorgan Chase
- Bank of America
- Wells Fargo
- Citigroup
These banks hold about 45% of all U.S. customer deposits as of recent years and are among the largest by assets and market capitalization globally.
In Australia:
The Big 4 banks are:
- Commonwealth Bank of Australia (CBA)
- Westpac
- National Australia Bank (NAB)
- Australia and New Zealand Banking Group (ANZ)
These banks dominate the Australian banking market, together holding around 70% of the financial sector market share, with combined assets exceeding $3.8 trillion as of early 2025. They are also regulated under a 'four pillars policy' that prevents them from merging with each other.
Other contexts:
The term "Big 4 banks" can also apply to major banking groups in other countries, such as Vietnam, where the top four banks are Vietcombank, Agribank, BIDV, and Vietinbank.
In summary, the exact identity of the Big 4 banks depends on the country context, with the term commonly describing the four largest and most influential banks in that country or region. The most referenced Big 4 globally are those in the United States and Australia.
