Yield Calculation 

The yield calculation for preferred shares as currently stated is incorrect. You cannot calculate yield of preferred shares with a bond calculator due to accrued interest  bonds got it, prefs don't. Additionally, while the sum of current yield and amortization of the discount/premium to redemption is a good approximation of the yield, it should be clearly stated that it is only a rough approximation - even when the amortization is calculated as carefully as suggested. See http://www.himivest.com/media/moneysaver_0607.pdf for a discussion (and link to a calculator) of preferred share yield calculation.