Sales & Trading is the division within an investment bank responsible for market-making, buying and selling securities on behalf of clients. Salespeople build relationships with institutional clients to understand their investment needs, while traders execute the transactions. This division is the profit center for banks, helping clients move large amounts of capital efficiently. Major players include Goldman Sachs, Morgan Stanley, and Bank of America.

https://www.investopedia.com/articles/investing/011216/career-guide-sales-and-trading.asp