Indexation allowance was introduced in the 1970s to provide relief from paying tax on inflationary gains based on increases in RPI. The relief was abolished in 1998 for individuals and trusts, and replaced with taper relief. However, it was retained for companies. The Autumn Budget announced that indexation for corporation tax would cease for disposals from January 2018 onwards, although indexation up to December 2017 would be retained.
Although the change will apply to all chargeable assets owned by companies, it will have a significant impact on property investment companies where indexation allowance acted as a shelter from inflationary gains.