There are different types of debt that exist today, some of which are basic loans, bonds, syndicated loans and promissory notes. Debt, especially when the sums of money 
involved are large, can be secured through a mortgage or other kinds of security interest over some of the debtor's property; in this case the creditor usually has certain rights over that property in the event that the debtor becomes unable to repay the debt and defaults on the loan, for some reason.

A basic loan is the simplest form of debt and this consists of an agreement to lend a principal sum of money for a fixed period of time, which is to be repaid by a certain date. In commercial loans as a norm, the interest is calculated as a percentage of the principal sum per annum, and will also have to be paid to the creditor by the same date. It is usually paid back monthly, or half yearly, in equal payments over the period of the loan. It can also sometimes be paid back all at once at a later date in which case it is called a balloon payment.

A bond is a debt security which can only be issued by certain institutions, such as certain companies and government bodies. A bond entitles the holder to repayments in terms of interest as well as principal. When such an institution wishes to borrow money it resorts to selling bonds in the marketplace to investors. They will usually have a fixed lifetime ranging from 3 to 50 years, long term bonds tend to be less common though; and at the end of that period the money will be repaid in full. During the period the borrower will be required to pay an interest known as a coupon for bonds at regular intervals. Bonds are usually traded in the bond markets, and are widely used as relatively safe investments as compared to shares.

A syndicated loan is one that is granted to companies that wish to borrow more money than what any single lender might be prepared to risk in a single loan, the requirement for this usually arises when the amount runs into many millions of a particular currency. A syndicate of banks is created, and each bank agrees to put forward a portion of the principal sum.

A promissory note is usually a contract detailing the terms of a promise by one party, who is the maker, to pay a sum of money to the other who is the payee. The obligation may arise from the repayment of a loan or from any other form of debt. For instance, in the sale of a business, the purchase price might be a combination of an immediate cash payment and one or more promissory notes for the balance that is yet to be paid at a later date. The terms of a note typically include the principal amount, the interest rate if any, and the maturity date. A promissory note differs from an IOU in sense that the latter is a simple acknowledgement of the existence of a debt owed, whereas a promissory note, as its name implies, contains a more affirmative undertaking to repay the amount stated to be borrowed.