SEIS Tax Relief Calculator 2025/26

SEIS stands for Seed Enterprise Investment Scheme. It is a UK government scheme that offers 50% income tax relief to investors who subscribe for new shares in qualifying early-stage UK companies. SEIS is designed to encourage investment in very early-stage businesses that are inherently high-risk. In addition to income tax relief, SEIS investors benefit from CGT exemption on gains from qualifying shares held 3+ years, and loss relief if the company fails.

Each investor can invest up to £200,000 per tax year under SEIS (increased from £100,000 from April 2023). The income tax relief is 50% of the investment, so the maximum annual tax relief is £100,000. Relief can be carried back one tax year if you have unused relief capacity. Companies can raise up to £250,000 under SEIS (increased from £150,000 from April 2023) before seeking further investment under EIS or other routes.

If the company fails and the shares become worthless, the investor can claim loss relief. The loss is calculated as the original investment minus the income tax relief already received. For example: £20,000 invested, £10,000 income tax relief received, net loss = £10,000. This net loss can be set against income (reducing income tax) or capital gains. Combined with the income tax relief already received, the effective downside risk on a SEIS investment is significantly reduced.