Credit instruments are various legally valid written certificates issued when financing is conducted between capital suppliers and capital demanders.

A credit card is a special carrier card with consumer credit issued by a bank or credit card company. The cardholder can use it to shop and consume from a special agency or deposit and withdraw cash from a designated bank. It is a credit instrument.

Credit instruments also include: money orders, cashier's checks, checks, letters of credit, credit cards, large negotiable certificates of deposit, stocks, and bonds. Credit cards integrate deposits, withdrawals, consumption, settlement, and inquiries, which can reduce the use of cash, simplify payment procedures, facilitate shopping and consumption, enhance consumption safety, and bring many conveniences to cardholders.