|This article does not cite any references or sources. (August 2009)|
A bond selling at par has a coupon rate such that the bond is worth an amount equivalent to its original issue value or its value upon redemption at maturity. This amount is typically $1000 per bond.
Par value stock has no relation to market value and, as a concept, is somewhat archaic. The par value of a share of stock is the value stated in the corporate charter below which shares of that class cannot be sold upon initial offering; the issuing company promises not to issue further shares below par value, so investors can be confident that no one else will receive a more favorable issue price. Thus, par value is the nominal value of a security which is determined by the issuing company to be its minimum price. This was far more important in unregulated equity markets than in the regulated markets that exist today. The par value of stock remains unchanged in a bonus stock issue but it changes in a stock split.
Par value also has accounting purposes. It allows the company to put a de minimis value for the stock on the company's financial statement.
Many common stocks issued today do not have par values; those that do (usually only in jurisdictions where par values are required by law) have extremely low par values (often the smallest unit of currency in circulation), for example a penny par value on a stock issued at USD$25/share. Most states do not allow a company to issue stock below par value.
Even in jurisdictions that permit the issue of stock with no par value, the par value of a stock may affect its tax treatment. For example, Delaware permits the issue of stock either with or without a par value, but by choosing to assign a par value, a corporation may significantly reduce its franchise tax liability.
No-par stocks have "no par value" printed on their certificates. Instead of par value, some U.S. states allow no-par stocks to have a stated value, set by the board of directors of the corporation, which serves the same purpose as par value in setting the minimum legal capital that the corporation must have after paying any dividends or buying back its stock.
Also, par value still matters for a callable common stock: the call price is usually either par value or a small fixed percentage over par value.
In the United States, it is legal for a corporation to issue "watered" shares below par value. However, the purchasers of "watered" shares incur an accounting liability to the corporation for the difference between the par value and the price they paid.
The term "at par" is also used when two currencies are exchanged at equal value (for instance, in 1964, Trinidad and Tobago switched from British West Indies dollar to the new Trinidad and Tobago dollar, and that switch was "at par", meaning that the Central Bank of Trinidad and Tobago replaced each old dollar with a new one).