In the context of a bulge bracket investment bank, it's basically like this: Front office - S&T (sales & trading), i.e. revenue generating activity. Usually in

In the context of a bulge bracket investment bank, it's basically like this: Front office - S&T (sales & trading), i.e. revenue generating activity. Usually includes any quants/quant developers actively working on things that make money Middle office - operations. handles settlements, confirms, and generally anything related to the post-trade flow that is "after the trade is booked" Back office - accounting, legal, engineering, IT support, HR. Anything that isn't a revenue center that also isn't even tangentially facing revenue generating operations