C2.611 Time apportionment
The provisions below only apply to companies (see C2.610).
Apart from the special rules for quoted securities, units in a unit trust scheme, and land or an estate in the UK reflecting development value, there are general rules for other assets1. The main rule for these other assets is that the gain on disposal is treated as having accrued evenly over the whole period of ownership2, though the beginning of the period of growth cannot be treated as having started earlier than 6 April 19453. The chargeable gain is that proportion of the whole gain which the period from 6 April 1965 to the date of disposal bears to the whole period of ownership4; though, where the period of ownership started before 6 April 1945, the whole period of ownership is treated as the period from 6 April 1945 to the date of disposal5. A taxpayer may elect to have the amount of his chargeable gain determined by reference to the market value of the asset at 6 April 1965, instead of under the general time apportionment rule6 (see C2.612).
For disposals made after 5 April 1998, the 31 March 1982 market value is substituted as the base cost if a rebasing election7 has been made. In such cases, time apportionment of the gain is not necessary8; the gain or loss is computed by reference solely to the value of the asset at 31 March 1982 and the amounts of any allowable expenditure incurred after that date. If a