What it means
An option pool is a promise written into the capital structure: a fixed number of shares the board is authorised to hand out as options over the coming years. Nobody owns those shares yet, but they are counted in the fully diluted share count so that ownership percentages reflect the eventual reality rather than today's snapshot.
The pool matters because young companies rarely pay top-of-market salaries. Options let a business recruit senior people by offering a slice of future value instead of cash today, and a pre-agreed pool means the board can make offers quickly without going back to every shareholder for approval.
Pool size is usually expressed as a percentage of the fully diluted share count, commonly somewhere between 10% and 20% at an early funding round. Investors normally insist the pool is created or topped up immediately before their money goes in, which means the dilution falls on existing shareholders rather than being shared with the incoming investor.
Grants from the pool almost always vest over time, often four years with a one-year cliff, meaning nothing vests until the first anniversary. Unvested options belonging to leavers return to the pool and can be regranted, so a well managed pool partly recycles itself rather than draining in a straight line.
The nuance worth knowing is the difference between a pool measured before the round closes and one measured after it. The wording sounds like lawyers' detail, but it can move founder ownership by several percentage points, so it is worth modelling both versions before signing a term sheet.
In practice
Real-world examples.
Example
A payments startup raising a Series A is told by its lead investor to create a 15% pool before closing. The founders push back and negotiate 12%, arguing that their next four senior hires are already identified and cost less equity than the investor assumed. The compromise saves the founding team roughly three percentage points of ownership.
Example
A veterinary clinic group offers share options to its four regional managers to stop them being poached by a larger chain. The board reserves 200,000 shares, grants 40,000 to each manager on a four-year vesting schedule, and keeps 40,000 back for a future finance director.
Example
A logistics software company discovers its pool is almost exhausted two years after its last raise, with only 30,000 shares left against a hiring plan needing 250,000. The board asks shareholders to approve a top-up, which dilutes everyone but is cheaper than losing candidates to better-funded rivals.
Formula
Calculation
Option pool percentage = shares reserved in the pool / fully diluted shares outstanding
A company agrees with its investors that the fully diluted share count immediately after the round will be 10,000,000 shares, of which 15% is reserved for the team. The pool is therefore 10,000,000 x 15% = 1,500,000 shares, and every other holder combined accounts for 10,000,000 - 1,500,000 = 8,500,000 shares.
A founder holding 4,000,000 shares owned 4,000,000 / 8,500,000 = 47.1% before the pool was carved out, and 4,000,000 / 10,000,000 = 40.0% after it, a loss of 7.1 percentage points. The board then grants 950,000 options, leaving 1,500,000 - 950,000 = 550,000 shares unallocated for future hires. A new VP of Engineering receives 100,000 of those options at a strike price of $1.20; if the shares are later worth $9.20 each, the gain on exercise is 100,000 x ($9.20 - $1.20) = $800,000.Case study
Seen in the real world.
Larkfield Analytics is an illustrative, entirely fictional data business used here to show how an option pool behaves in practice. At incorporation its two founders held 4,000,000 shares each. When a venture fund offered $6,000,000 for 15% of the company, it also required a 15% option pool measured after the investment, bringing the fully diluted count to 10,000,000 shares.
The founders initially assumed the pool would dilute the investor too. Their adviser showed them that because the pool was carved out before the new money landed, the whole 15% came from their side: each founder fell from 47.1% to 40.0% of the fully diluted total. Armed with that number, they renegotiated the pool down to 12% by presenting a costed hiring plan for the next 24 months.
Two years later Larkfield had granted 940,000 of its 1,200,000 reserved shares, and departures had returned 85,000 unvested options to the pool. The finance director tracked the balance monthly alongside cash, treating unallocated options as a recruiting budget rather than a piece of legal paperwork.
Watch out
Common mistakes.
- Treating pool shares as already issued and worrying that they dilute the founders twice, when in fact the dilution happens once, at the moment the pool is reserved.
- Agreeing a pool percentage without checking whether it is measured before or after the new investment, which can quietly cost founders several percentage points.
- Sizing the pool by copying a percentage from another company instead of building it up from an actual hiring plan and the equity each role will realistically need.
Questions
People also ask.
Who decides how options are granted from the pool?
The board of directors, usually within limits set by shareholders, approves each grant including the number of shares, the strike price and the vesting schedule.
Does an unused option pool disappear at an exit?
No, unallocated shares simply are not issued, so the value that would have gone to those options is spread across the actual shareholders instead.
Is an option pool the same as issuing shares to employees?
No, an option is the right to buy shares later at a fixed price, so the employee only becomes a shareholder if and when they choose to exercise it.
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