Multiple conditional formatting - overcoming -ve divisors

Hi there,

I've been struggling with this for a few days and any help would be greatly appreciated!!

I'm trying to create a table that does basic investment portfolio attribution. So for example, if a particular holding has performed well in the portfolio, then it shows how much it has contributed to performance as a %. The formula is simple : performance of the holding * the weighting in the portfolio / the performance of the total portfolio for that time period.

The problem seems to be when you have a holding which has put in a negative number/performance over a given time period, but so has the portfolio. It gives it a positive attribution. The same is also true if the holding has put in a positive contribution, but the portfolio is negative over the time period.

I know that the answer to this problem is simple and must be some kind of IF, AND, THEN statement - but I don't know the code......

I've attached the spreadsheet . Any help would be gratefully received.

Cheers

Can anyone help me please?