Which service began using dollar-sign stock tags such as $XRX in 2009?

StockTwits began using dollar-sign stock tags such as $XRX in 2009. The service, built around real-time financial discussion, placed a dollar sign before a ticker symbol so users could clearly mark posts about a particular company or security.

This convention solved a practical problem in social-media finance. A company’s ticker can appear in ordinary text, but the leading dollar sign signals that the term is intended as a market symbol. That made conversations easier to filter and follow, especially in a fast-moving stream of investor commentary.

Twitter later adopted the format and called these links cashtags, supporting them officially in July 2012. The term is sometimes mistakenly attributed to Twitter because Twitter helped popularize the feature, but StockTwits used the convention first. The examples are ticker symbols, not hashtags: $XRX refers to Xerox’s ticker, while a topic label would begin with #.