Calculating the loss: what is an 'overall loss'?
The basic rule is that for relief to be available there must be an overall loss on the sales of qualifying investments (IHTM34131) sold by the appropriate person (IHTM34161) in the 12 months the death, IHTA84/S179 (1).
This means that all sales by the appropriate person(s) within this period have to be taken into account to see if there is an overall loss. The relief will only apply if the gross proceeds of all the qualifying investments that are sold are less than the date of death value of those investments.
If there is both free estate and settled property you should treat the claims by the legal personal representatives and trustees entirely separately and calculate the overall loss at each title.