Consumer celebrity Clark Howard recently shared the rule of thumb that, on average, the larger the bank, the poorer the customer service. If this is true, it may not be too encouraging to know that among industry sectors, banks are one type of business dominated by enormous mega-firms. Here, each the top 30 largest banks by market cap as of January 2017 has a market cap of over US$50 billion:
| RIC | Name | USD Market Cap (Millions) |
| JPM | JPMorgan Chase & Co | $310,987 |
| WFC | Wells Fargo & Co | $281,500 |
| BAC | Bank of America Corp | $227,667 |
| 1398.HK | Industrial and Commercial Bank of China Ltd | $224,461 |
| 0939.HK | China Construction Bank Corp | $189,270 |
| 3988.HK | Bank of China Ltd | $185,685 |
| C | Citigroup Inc | $172,665 |
| HSBA.L | HSBC Holdings PLC | $163,171 |
| 1288.HK | Agricultural Bank of China Ltd | $144,905 |
| 3328.HK | Bank of Communications Co Ltd | $117,441 |
| RY.TO | Royal Bank of Canada | $104,211 |
| CBA.AX | Commonwealth Bank of Australia | $103,552 |
| USB | U.S. Bancorp | $88,111 |
| 8306.T / MTU | Mitsubishi UFJ Financial Group Inc | $87,885 |
| BNPP.PA | BNP Paribas SA | $80,989 |
| WBC.AX / WBK | Westpac Banking Corp | $80,650 |
| SAN.MC / SAN | Banco Santander SA | $78,212 |
| TD.TO | Toronto-Dominion Bank | $70,993 |
| BNS.TO | Bank of Nova Scotia | $68,788 |
| ITUB.K | Itau Unibanco Holding SA | $67,567 |
| ANZ.AX / ANZBY.PK | Australia and New Zealand Banking Group Ltd | $65,233 |
| 3968.HK | China Merchants Bank Co Ltd | $64,225 |
| NAB.AX / NABZY.PK | National Australia Bank Ltd | $60,204 |
| PNC | PNC Financial Services Group Inc | $57,879 |
| LLOY.L / LYG | Lloyds Banking Group PLC | $56,722 |
| ING | ING Groep NV | $56,088 |
| SMFG.K | Sumitomo Mitsui Financial Group Inc | $54,802 |
| 7182.T | Japan Post Bank Co Ltd | $54,079 |
| 8316.T | Sumitomo Mitsui Financial Group Inc | $54,020 |
| BBD | Banco Bradesco SA | $51,012 |