Symbology

This page summarizes how Clear Street Studio API's handle symbology in its APIs, both for REST and WebSocket APIs.

What is a "symbol"

A symbol is an alias to an instrument that is tradable in some market. Instruments are formal financial contracts that are exchanged between interested parties. For example, shares in Apple represent an equity instrument that is traded on all U.S. equity exchanges. This equity instrument has a multiple symbols, including a ticker (AAPL), a CUSIP (037833100), etc. The symbol itself isn't what's traded, it's the instrument.

All Studio APIs use a symbol field to indirectly reference the traded instrument.

Symbol Formats

When sending a request message that has a symbol field, it will always be accompanied with a symbol_format field. This field is a well-defined enumerated type, discussed below, that indicates the format that symbol is in. The combination of the symbol and symbol_format field uniquely resolve to the tradable instrument.

Below are the format we currently support.

CMS

The CMS symbol format refers to U.S. equity stock tickers, e.g. AAPL, MSFT, etc. This is the default format the API will assume you're using if you don't provide a symbol_format field.

OSI

OSI stands for Options Symbology Initiative and is used to refer to listed U.S. equity options, e.g. SPX 141122P00019500.