520-050 Part-disposals: apportionment of base cost
On a part-disposal of an asset, unless expenditure is wholly attributable to what is disposed of or what is retained, each item of the ‘base cost’ (see ¶519-500) of an asset is apportioned to each part (TCGA 1992, s. 42(1), (4); for the concept of part-disposals, see ¶514-100).
An apportionment is, for this purpose, carried out by allocating to the part disposed of the following proportion of each item of the base cost, the remainder being allocated to the part retained (TCGA 1992, s. 42(2)):
A/A + B
where A is the amount or value of the consideration; and