ORIGINAL ISSUE DISCOUNT (O.I.D.) – An amount by which the par value of a security exceeded its public offering price at the time of its original issuance. The original issue discount is amortized over the life of the security and, on a municipal security, is generally treated as tax-exempt interest. When the investor sells the security before maturity, any profit realized on such sale is calculated (for tax purposes) on the adjusted book value, which is calculated for each year the security is outstanding by adding the accretion value to the original offering price. The amount of the accretion value (and the existence and total amount of original issue discount) is determined in accordance with the provisions of the Internal Revenue Code and the rules and regulations of the Internal Revenue Service. Compare: MARKET DISCOUNT BOND. See: ACCRETION OF DISCOUNT; COMPOUND ACCRETED VALUE; DISCOUNT.