EMI vs CSOP vs Growth Shares: Tax-Efficient Equity for Your First Hires

Equity is the most powerful retention tool a startup has — and the easiest to mishandle. Hand it out informally and you create unexpected income tax bills, NIC liabilities and angry employees. Use the right HMRC-approved scheme and the same equity becomes a 10% capital gains event with the team firmly aligned to the exit.

EMI — the gold standard for early-stage UK startups

Who can use it. Trading companies with under 250 employees, gross assets under £30m, and not in an excluded sector. Most software, AI and tech companies qualify.

How it works. Employees are granted options at a strike price agreed with HMRC. No income tax or NIC on grant. On exercise, no income tax (assuming strike price equals or exceeds market value at grant). On sale, gains taxed at Business Asset Disposal Relief rates — 14% from April 2025 — up to £1m lifetime allowance.

The catch. Limits: £250k of options per employee, £3m company-wide. Working time test (25 hours/week or 75% of working time).

CSOP — when EMI is not available

Company Share Option Plan suits larger or later-stage companies that have outgrown EMI. The 2023 reforms doubled the limit to £60k per employee and removed the share class restrictions. Tax treatment is similar to EMI but without the BADR rate on exit — gains taxed at standard CGT rates (24% from April 2025).

Growth shares — when options will not work

Useful when EMI/CSOP do not fit (e.g. non-employees, advisors, contractors, or co-founders joining post-incorporation). Growth shares are a separate share class with a hurdle — they only have value above a defined threshold (typically current valuation). Holders pay a small amount for them upfront, and all future growth is taxed as capital gains.

The trap. Get the hurdle wrong (set too low) and HMRC treats the difference as employment income — disastrous tax bill. Always get a valuation.

How to choose

• UK employees, eligible company → EMI almost always wins.
• Larger company or non-qualifying sector → CSOP.
• Advisors, contractors, non-UK people, or unusual structures → growth shares.
• Need to share value but cannot dilute the cap table → phantom equity (cash-settled) — different beast, separate post.

What to avoid

• Verbal promises of equity — legally messy, taxed as income when honoured.
• Granting options without a board minute and HMRC valuation — voids the EMI tax treatment.
• Forgetting to file the annual ERS return (deadline 6 July) — automatic penalties.
• Letting departing leavers keep vested options indefinitely — clogs the cap table for years.