Dwellings subject to ATED: computation of gains and losses: general
TCGA92/S57A and Sch 4ZZA contain the general rules for computing gains and losses that are ATED-related and that are not ATED-related on disposals. The ATED-related gain or loss may be subject to further adjustment to give a form of marginal relief or restriction, see CG73650 and CG73655. The non ATED-related gain or loss may comprise two elements: the gain/loss for the period up to 5 April 2013 and the gain/loss from 6 April 2013 to the date of disposal which is not ATED-related.
A general computational feature of the rules in Schedule 4ZZA is that indexation allowance is available only against non ATED-related gains.
Detailed guidance on how to compute ATED-related related gains and losses is at CG73626 to CG73638. Guidance on how ATED-related gains and losses are brought into charge to (or relief from) capital gains tax and how non ATED-related gains and losses are dealt with are at CG73648 to CG73665.
If a disposal to which the rules in Schedule 4ZZA apply does not produce an ATED-related gain or an ATED-related loss, then the normal computational rules for capital gains should be applied.