The extent by which the conversion price of a convertible security exceeds the prevailing common stock price at the time the convertible security is issued. In general usage, the conversion premium is the amount by which the convertible security trades above its conversted value. For example, if a $1,000 par bond is trading at $1,100, it is convertible into 50 shares, and the shares are trading at $21, the converted value is 50 X 20.50 = $1,025, and the conversion premium is $75.
The excess at which a convertible security sells above its conversion value. The conversion premium usually declines as a convertible security rises in market price. A bond trading at $1,400 and convertible into 50 shares of common stock with a current market price of $22 each sells at a conversion premium of $1,400 - (50 × $22), or $300.