Fixed Income Portfolios

Hi, I’m trying to display the change in market value of a single currency fixed income portfolio from one period to another. The formula I’m using is as follows: Beginning Market Value + Net Contributions & Withdrawals by the client + Investment Income + Change in Unrealised Gain/(Loss) - Bond Amortization + Realised Gain/(Loss) = Ending Market Value This formula is missing something because I’m not getting where I want to be. Can somebody shed some light on what I’m doing wrong? Thanks, Soddy.