The term is typically reserved for the trading activities done by sell-side investment banks who are primarily engaged in making markets for institutional clients in various forms of securities.
These desks will more generally fall within the categories of fixed income, currencies, commodities, or equities.
The sales role is the client-facing role of the S&T division of a bank, which thus necessitates sales members interacting directly with institutional clients in order to assess their needs, provide general market commentary, and work with other members of the desk such as traders or structurers in order to price and execute their desired trades.
This strategy often affects the way the firm will operate in the market, the direction it would like to take in terms of its proprietary and flow positions, the suggestions salespersons give to clients, as well as the way structurers create new products.
The necessity for numerical ability in sales and trading has created jobs for physics, math and engineering Ph.D.s who act as quantitative analysts.