For the purposes of corporation tax this section and section 114—
On any disposal of a section 104 holding, other than a disposal of the whole of it—
On a disposal of the whole of a section 104 holding, the indexation allowance is the amount by which the indexed pool of expenditure at the time of the disposal exceeds the qualifying expenditure at that time.
In relation to a section 104 holding, the qualifying expenditure is at any time the amount which would be the aggregate of the relevant allowable expenditure in relation to a disposal of the whole of the holding occurring at that time.
Subject to subsection (6) below and section 114 the indexed pool of expenditure shall come into being at the time that the holding comes into being or, if it is earlier, when any of the qualifying expenditure is incurred and shall at the time it comes into being be the same as the qualifying expenditure at that time.
In relation to a section 104 holding which was in existence immediately before the coming into force of this section, the indexed pool of expenditure on the coming into force of this section shall be the same as it was for the purposes of Part III of Schedule 19 to the Finance Act 1985 immediately before then.
Where a disposal to a person acquiring or adding to a section 104 holding is treated by virtue of any enactment as one on which neither a gain nor a loss accrues to the person making the disposal—
Any reference below to an operative event is a reference to any event (whether a disposal or otherwise) which has the effect of reducing or increasing the qualifying expenditure referable to the section 104 holding.
Whenever an operative event occurs—
Where the operative event is a disposal—
At the time of any operative event, the indexed rise in the indexed pool of expenditure is a sum produced by multiplying the value of the pool immediately before the event by a figure expressed as a decimal and determined, subject to subsection (11) below, by the formula—
The indexed rise is nil if—