An investor is an individual or entity that utilizes its capital or the capital of others with the goal of receiving a return. Investors can range from a person buying stocks at home on their online brokerage account to multi-billion dollar funds investing globally. If you invest in a company, the most important thing is the bottom line. You want to know how much the company earns and whether it's boosting its sales. This can tell you whether a company is on a growth trajectory or in decline, key factors that determine how much the company is worth.