Legal & Equity
Option Pool
Option Pool is a block of company shares set aside to grant as stock options to future employees, advisors, and contractors. It is reserved up front (usually 10 to 20 percent of equity) and dilutes the founders, not the new investors, when created before a round.
Also known as: equity pool, employee stock option pool (ESOP), stock option pool
Why it matters
The option pool is where validation reality collides with cap-table math, and most first-time founders get surprised by it. Investors almost always require you to create or top up the pool before their money goes in, which means the dilution lands entirely on you and your co-founders, not them. A 15 percent pool carved out pre-money can quietly knock several points off your effective pre-money valuation, so a headline number that looks generous can be worth a lot less once you do the math. Before you have product-market fit, do not over-reserve: a big pool signals you plan to hire a team you cannot yet justify, and unallocated shares still count against your ownership. The right question pre-PMF is not 'how big should the pool be' but 'who are the two or three hires that actually move validation forward,' then size to that. Treat the pool as a hiring budget you are paying for in ownership, and only fund the headcount your evidence supports.
Formula
Post-financing pool % = shares reserved for options / total fully diluted shares after the round
Worked example
A founder raises a $2M round at a $8M pre-money valuation. The investor requires a 15 percent post-money option pool. Because the pool is created pre-money, the founders absorb all of it: the effective pre-money drops to roughly $6.5M, so the founders end up owning about 5 to 6 points less than the headline $8M/$10M split implied.
Common mistakes
- Accepting the investor's requested pool size without negotiating. The 'pool shuffle' (carving the pool out of pre-money) is a hidden discount on your valuation, so model it before signing the term sheet.
- Over-reserving before product-market fit. A 20 percent pool when you have no validated hiring plan just dilutes founders for headcount you cannot defend with evidence.
- Forgetting unallocated options return to the pool, not to founders. Good practice is to size the pool to a concrete 18 to 24 month hiring plan, then top up at the next round.
Frequently asked questions
What is a good option pool size?
For an early-stage startup, 10 to 15 percent fully diluted is typical, with later or hiring-heavy rounds pushing toward 20 percent. Bigger is not better: every unallocated share dilutes founders, so size the pool to a specific 18 to 24 month hiring plan rather than to a round-number percentage. If you cannot name the roles the pool will fill, it is too big.
How do you calculate the option pool?
Express it as a percentage of total fully diluted shares after the round, including the new investor shares and the pool itself. To hit a target post-money pool, you back-solve the share count so options equal that percentage of the final total. The 'fully diluted' part matters because it counts all reserved shares, not just the ones already granted.
Why does the option pool dilute founders and not investors?
Because investors require the pool to be created before their money goes in, it is carved out of the pre-money valuation. That means existing holders (the founders) absorb the dilution, while the new investor's percentage is calculated after the pool already exists. This is called the 'pool shuffle' and it effectively lowers your real pre-money valuation.
Option pool vs ESOP: what is the difference?
In US startup usage they usually mean the same thing: a reserve of shares for employee stock options. 'ESOP' (Employee Stock Ownership Plan) is the formal plan document and the broader term, while 'option pool' refers specifically to the block of shares set aside under it. Note that in the UK and some other markets 'ESOP' can mean a legally distinct structure, so confirm context.
Should I create an option pool before I have product-market fit?
Keep it small and concrete. Pre-PMF you do not yet know which hires move validation forward, so reserving 15 to 20 percent locks up ownership for a team you cannot justify. Reserve enough for the two or three near-term hires that actually advance the build-or-kill decision, and expand the pool when a round and a real hiring plan demand it.
Can you negotiate the option pool in a term sheet?
Yes, and you should. The pool size and whether it sits pre-money or post-money are both negotiable, and they directly change your effective valuation. Push to size the pool to an actual hiring plan rather than a generic percentage, and consider asking that any top-up come partly from post-money so the dilution is shared.
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Last updated 2026-06-09 · Back to the glossary