The buy-side is a term used in investment firms to refer to advising institutions and concerned with firms that purchase securities and include investment managers, pension funds, and hedge funds. Buy-side companies generally do not offer custody service.
Sell-Side firms are ones who are looking to pitch the assets such as stock, bonds, and foreign exchanges. Sell-side is used in the financial services industry, which creates and promotes the financial instruments products to a sale or make them available to buy-side entities involved in making the investments.