Dividends are a portion of a company's profit that is paid to the shareholders. Consequently, the amount of a dividend will vary depending on the company's profits. If a company is not making any profit at all, it is unlikely to pay a dividend to shareholders.
Interest is paid by the company on money it has borrowed (for example, by issuing Loan Stock to investors) and is usually paid in arrears at the rates and times specified in accordance with the terms and conditions.
