A bond is a fixed income instrument which represents a loan to a borrower (typically corporate or governmental) made by an investor. A agreement between the lender and the borrower which includes the details of the loan and its payments could be known as an I.O.U.. Bonds are used for the funding of infrastructure and activities by corporations, counties, states and sovereign governments.Bond owners are issuer debtors, or creditors. Bond details include the end date on which the principal of the loan is due to be paid to the bond owner and usually includes the terms of the borrower's variable or fixed interest payments.