Investment Income is money received in interest payments, dividends, capital gains realized with the sale of stock or other assets, and any additional profit made through an investment vehicle. It's basically a financial reward from lending or investing money in a particular investment.Investing in a company is not the only way to earn money. The money you get from interest payments, dividends, capital gains realized with the sale of stock or other assets, and any additional profit made through an investment vehicle are also considered as investment income.