The International Securities Identification Number (ISIN code) is a securities coding standard developed by the International Organization for Standardization (ISO) and was officially released in "Securities and Related Financial Instruments - International Securities Identification Numbering System" (ISO6166) . ISO6166 mainly stipulates the specific coding method and execution and maintenance organization of ISIN coding. The coding coverage includes financial instruments such as stocks, bonds, futures, options, and warrants. ISO6166 is currently accepted by many international organizations in the securities industry, such as the Group of 30 Experts on Securities Registration and Settlement (G30), the Committee on Payment and Settlement Systems of the Bank for International Settlements (CPSS), the International Organization of Securities Commissions (IOSCO), and the International Association of Securities Executives ( ISSA) all regard the application of ISIN codes as a major recommendation to measure the level of internationalization and standardization of a country or region's financial market. In terms of composition, the ISIN code consists of 12 letters or numbers, and mainly consists of three parts: the prefix is ??a country or region code (ISO3166) made up of 2 letters; the basic number is a 9-digit letter or number, which is composed of each country and region. Prepare it by yourself; the last digit is the check code. The Association of National Numbering Agencies (ANNA) is the global execution and maintenance organization for ISIN codes. A specific organization in a country or region can be responsible for preparing and maintaining ISIN codes for the securities of that country or region after applying to become an ANNA member (NNA).