A securities analyst who works in the research department of an institutional firm that is on the buy-side (so-called because these companies buy stocks and other securities on behalf of their clients). A typical buy-side firm is a mutual fund. A buy-side analystÂ’s research product is distributed only internally or to the firmÂ’s best clients. In contrast, the research of a sell-side analyst (whose firm is selling its trading and investment banking services to clients) is widely distributed to the public at large as well as the firmÂ’s clients.