The startup offer includes a £45,000 salary — slightly below market — plus “generous stock options”. Everyone nods as if this is obviously wonderful, but you have no idea what the options are actually worth, when you can use them, or what happens if the company fails. Understanding stock options at startups takes longer than most candidates expect — not because the concepts are complex, but because the details that determine their value are buried in legal documents nobody explains. This UK-focused guide covers how startup options work, what they are really worth, the tax position, and the questions to ask before you sign.
The fundamental deal: startups pay below-market salaries and compensate with equity — a share in the company’s future value. If the company succeeds spectacularly, early employees can make life-changing money; if it fails (and most startups do), the options are worthless. Options are a lottery ticket, not a salary — valuable, but never count them as guaranteed compensation.
How Stock Options Actually Work
A stock option gives you the right to buy shares at a fixed price (the “strike” or “exercise” price) in the future. If the company’s shares later become worth more than the strike price, you profit on the difference; if not, the options are worthless. You do not own anything until you exercise (buy) the shares — and exercising usually requires paying the strike price plus potential tax.
Vesting controls when you can exercise: the standard is four years with a one-year “cliff” — you get nothing if you leave within the first year, then 25% vests at year one, with the rest vesting monthly or quarterly after. Leave after two years and you keep roughly half your options; the rest evaporate. Some UK startups use “EMI schemes” (Enterprise Management Incentives) — the government’s tax-advantaged option scheme, and the structure you want: EMI options offer major tax benefits (more below) and signal the company is set up properly. Ask explicitly: “Are these EMI options?” If the answer is no or evasive, ask why — non-EMI options are taxed far more harshly. The gov.uk guidance on venture schemes and EMI documentation set out the official rules.
What Are They Actually Worth? The Honest Maths
Valuing startup options requires scepticism. Start with the current valuation: what did investors last pay per share (the “409A” or HMRC-agreed valuation for EMI)? Your strike price should be at or near this. Then assess the upside scenario honestly: for your options to be worth £100,000, the company’s share price must rise enough above your strike price, across your number of shares, after dilution from future funding rounds (each round typically dilutes existing shareholders 15–25%).
Work the example: 10,000 options at a £1 strike price, company currently valued at £10m. If the company exits at £100m (a 10x outcome — rare), and assuming 50% dilution along the way, your shares might be worth roughly £5 each: £50,000 gross, before tax. If it exits at £20m, perhaps £5,000–£10,000. If it fails: zero. Most startup employees would be wise to value their options at 10–20% of the rosy scenario for decision-making — and to remember that salary is certain while options are speculative. Never accept a below-market salary solely for options unless you can afford the salary and genuinely believe in the upside. MoneyHelper offers general guidance on understanding equity compensation as part of financial planning.
UK Tax: EMI vs Non-EMI (This Matters Enormously)
EMI options are the gold standard: no income tax or National Insurance when granted or when exercised (provided the strike price was at least the market value at grant), and only Capital Gains Tax (currently 10% with Business Asset Disposal Relief up to £1m lifetime, otherwise 20%) when you eventually sell the shares. On a £50,000 gain, that is £5,000–£10,000 tax versus potentially £20,000+ under non-EMI treatment.
Non-EMI options face income tax and NI on the difference between strike price and market value at exercise — which can create the nightmare scenario of a large tax bill on shares you cannot yet sell (if the company has not exited). Limits apply: EMI covers companies with under 250 employees and £30m gross assets, options up to £250,000 per employee. Always confirm EMI status in writing before accepting — it is the single most important tax question in the offer. And get independent financial advice before exercising significant options; the sums and timing decisions (exercise early vs at exit) have real tax consequences.
Questions to Ask Before You Accept
Ask for: the number of options and what percentage of the company that represents (10,000 options means nothing; 0.1% means something); the strike price and current valuation basis; the vesting schedule and cliff; EMI confirmation in writing; what happens to vested options if you leave (the “post-termination exercise window” — standard is 90 days, which can force a painful buy-or-lose decision); the company’s funding history and runway (how many months until they need more money); and liquidation preferences (investors often get paid first in an exit — a £50m exit does not mean £50m shared among shareholders).
Evaluate the answers like an investor, because that is what you are becoming: strong revenue growth, credible investors, a long runway and honest answers are green flags; evasiveness about valuation, tiny option percentages dressed as “generous”, and pressure to decide quickly are red. And keep perspective: options are one component of the offer — weigh them alongside salary, role quality, learning and life fit, using the same total-compensation thinking as any job decision. For the broader financial picture, our guides to budgeting and saving effectively and saving on everyday expenses help you manage the cash-flow reality of startup salaries.
The Bottom Line
Startup stock options give you the right to buy shares at today’s price and profit if the company grows — valuable if it succeeds, worthless if it fails. Confirm EMI status in writing (the tax difference is enormous), understand your percentage ownership and vesting, value the options sceptically (10–20% of the rosy scenario), check the exercise window if you leave, and never trade essential salary for options alone. Treat the offer like the investment it is: exciting, potentially lucrative, and deserving of proper due diligence before you sign.
Frequently Asked Questions
What are EMI stock options?
Enterprise Management Incentives — the UK’s tax-advantaged employee share scheme. EMI options attract no income tax/NI on exercise and only Capital Gains Tax (10% with BADR) on sale, making them vastly more valuable than non-EMI options.
How much are startup stock options worth?
It depends on the company’s exit valuation, your percentage ownership, dilution from future funding, and tax treatment. Work scenarios sceptically: most startups fail (options worth zero); a 10x exit might make early-employee options worth tens of thousands after tax.
What happens to my stock options if I leave a startup?
You typically keep vested options but lose unvested ones, and must usually exercise vested options within ~90 days of leaving (the post-termination window) or lose them — check this clause before accepting.
What is a vesting cliff?
A standard term where no options vest in the first year — leave before 12 months and you get nothing. After the cliff, vesting typically proceeds monthly or quarterly over four years total.
Should I accept lower salary for more stock options?
Only if you can comfortably afford the salary and genuinely believe in the company’s prospects. Value options at a fraction of their best-case scenario for decision-making — salary is certain, options are speculative.
