A bank officer is an employee of a bank endowed with the legal capacity to agree to and sign documents on behalf of the institution. The title is usually held by branch managers, assistant managers, loan officers, and other experienced personnel. Executives and others holding titles such as "Vice President" are considered officers of the bank for legal purposes.

The title is also used to designate those branch personnel who act in a supervisory capacity. In larger banks, an officer at the branch level sometimes reviews accounts and makes decisions on whether to honour NSF items or to return them. Such decisions are usually left up to those who are legally responsible to act on behalf of the bank

 bank is a government-licensed financial institution^{[citation needed]} whose primary activity is to lend money. Many other financial activities were allowed over time. For example banks are important players in financial markets and offer financial services such as investment funds. In some countries such as Germany, banks have historically owned major stakes in industrial corporations while in other countries such as the United States banks are prohibited from owning non-financial companies. In Japan, banks are usually the nexus of a cross-share holding entity known as the zaibatsu. In France, bancassurance is prevalent, as most banks offer insurance services (and now real estate services) to their clients.

The level of government regulation of the banking industry varies widely, with counties such as Iceland, the United Kingdom and the United States having relatively light regulation of the banking sector, and countries such as China having relatively heavier regulation (including stricter

Banks act as payment agents by conducting checking or current accounts for customers, paying cheques drawn by customers on the bank, and collecting cheques deposited to customers' current accounts. Banks also enable customer payments via other payment methods such as telegraphic transfer, EFTPOS, and ATM.

Banks borrow money by accepting funds deposited on current accounts, by accepting term deposits, and by issuing debt securities such as banknotes and bonds. Banks lend money by making advances to customers on current accounts, by making installment loans, and by investing in marketable debt securities and other forms of money lending.

Banks provide almost all payment services, and a bank account is considered indispensable by most businesses, individuals and governments. Non-banks that provide payment services such as remittance companies are not normally considered an adequate substitute for having a bank account.

Banks borrow most funds from households and non-financial businesses, and lend most funds to households and non-financial businesses, but non-bank lenders provide a significant and in many cases adequate substitute for bank loans, and money market funds, cash management trusts and other non-bank financial institutions in many cases provide an adequate substitute to banks for lending savings to.