Definition
The 30% intensity threshold is the test that determines whether a loss-making UK SME qualifies for Enhanced R&D Intensive Support. The company's qualifying R&D expenditure must be at least 30% of its total expenditure in the accounting period. Total expenditure is based on amounts recognised in the profit and loss account for accounting purposes, with specified adjustments, and is aggregated across connected companies. The threshold was 40% for accounting periods beginning on or after 1 April 2023 and was reduced to 30% from 1 April 2024.
How HMRC defines it
HMRC guidance on the intensity calculation is at CIRD90720 and CIRD90740 of the CIRD Manual. The legislation is in Chapter 2 of Part 13 of the Corporation Tax Act 2009 as amended. The connected-company aggregation rules are derived from section 1138 of that Act.
Practical example
A pre-revenue start-up has total accounting expenditure of £800,000 in its year ended 31 March 2025, of which £280,000 is qualifying R&D. The intensity ratio is 35%, above the 30% threshold, so the company qualifies for ERIS and claims at the 27% rate rather than the merged scheme 20%.