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Digital assets and currencies

Understand assets, networks and trading mechanics with sources you can check.

Payments & settlement

American Express

American Express Company (Amex) is an American bank holding company and multinational financial services corporation that specializes in payment cards. It is headquartered at 200 Vesey Street, also known as American Express Tower, in the Battery Park City neighborhood of Lower Manhattan; in 2026, the company announced that it would develop and be the sole occupant of the new 2 World Trad

Payments & settlement

Centurion Card

The American Express Centurion Card, colloquially known as the Black Card, is an exclusive invitation-only charge card issued by American Express. It is reserved for the company's wealthiest clients who meet certain net worth, credit quality, and spending requirements on its gateway card, the Platinum Card. The firm does not disclose the exact requirements to receive an invitation to car

Payments & settlement

Charge card

A charge card is a type of credit card that enables the cardholder to make purchases which are paid for by the card issuer, to whom the cardholder becomes indebted. The cardholder is obliged to repay the debt to the card issuer in full by the due date, usually on a monthly basis, or be subject to late fees and restrictions on further card use. Charge cards are distinct from traditional c

Fiat currencies

Numismatics

Numismatics is the study or collection of currency, including coins, tokens, paper money, medals, and related objects.

Trading basics

Traveller's cheque

A traveller's cheque is a medium of exchange that can be used in place of the currency of a country. Each cheque is denominated in a preprinted fixed, round, amount of one of a number of major world currencies; it has two panels for a signature. The purchaser signs one panel of each cheque on receiving it; to use it, it is signed on the second panel and dated in the presence of the payee