The nominal value, or book value, of a share is usually assigned when the stock is issued. Market value reflects what the market is willing to pay for it. These two values may differ tremendously as a result of different market conditions as well as supply and demand.

Nominal value is also known as face value or par value. It is the stated worth of an asset. Most likely, this was the value of the asset at the time it was issued, such as cash, bonds and stocks.