ISO/TR 21797:2019 gives an overview of existing and currently used financial instrument identifiers. It shows which instrument identifiers, ticker symbols and proprietary codes are assigned via a standardized scheme to instruments of all asset classes. It focuses on providing an overview of the landscape and not on evaluating the schemes. Several aspects of the detailed trade cycle (a few examples being book building/primary, order entry management, execution management and trade confirmation matching) are excluded as their complexity would reduce the readability of the overview. Similarly, the level of complexity involved in properly representing the shifting perspectives of what is considered a financial instrument, based on a particular function being performed, is excluded.