How are mezzanine securities valued?

KOFIA guidelines require the fair value of mezzanine securities to be measured by splitting it into a bond value and an option value.

The bond value is calculated from the coupon rate, the guaranteed yield to maturity, the remaining maturity and a discount rate matching the issuer's credit rating, while the option value is calculated from the current share price, share price volatility, and the exercise prices and exercise periods of the conversion right, the early redemption right and the call option (right to demand sale). As a result, the value of a mezzanine security changes not only with interest rates and credit quality but also with the share price and its volatility.