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‹ HR Glossary

Employee stock options

Pay and remuneration
What are employee stock options?

Employee stock options give the right, not the obligation, to buy company shares at a fixed exercise (strike) price for a set period. The value is the growth above the strike: options on a company that never rises past it expire worthless, which is why they are the classic startup instrument.

The mechanics

A grant of options at a $1.00 strike is worth nothing while the shares trade at $1.00, and $3.00 per option if they reach $4.00: leverage in both directions. Options vest like any equity, and once vested must be exercised (bought at the strike) before they expire, either during employment or within a post-termination window that is often brutally short, 90 days being the startup convention that catches leavers who cannot fund the exercise cost and its tax.

Why startups use them

Early-stage companies can set low strikes, so joiners get maximum leverage on growth, and no cash changes hands until exercise. The trade is risk: most startup options expire worthless, a base rate every candidate should price in. The questions that separate real option value from decoration: strike versus latest valuation, percentage of the company, the post-termination exercise window, and what happens on acquisition.

Tax, at concept level

Regimes differ but the shape recurs: somewhere between exercise and sale, the gain over the strike is taxed, with special schemes in several countries (qualified plans in the US, start-up concessions in Australia, approved schemes in the UK) softening the treatment when conditions are met. The timing traps are real, tax can fall due before the shares can be sold in private companies, so specific advice at grant and before exercise is not optional.

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Common questions

What happens to options when I leave?

Vested options usually must be exercised within a post-termination window (often 90 days at startups) or they lapse; unvested options are forfeited. The window length is one of the most negotiable and least negotiated terms in equity.

What does "underwater" mean?

Options whose strike price is above the current share value. Underwater options have no exercise value; they only recover if the price does.

This page is general information, not legal advice. We check figures annually and update them on a best-efforts basis, but employment rules change and we cannot promise everything here is current or complete. Before you act on it, confirm the detail with the official source for your jurisdiction or your own adviser. Last reviewed July 2026.