Option pools and employee equity: ISOs, NSOs, RSUs, BSPCE, EMI

Startups face a structural compensation problem. They want to hire talent — engineers, executives, sales leaders — but they cannot pay competitive cash salaries because they have limited capital. The solution that emerged in 20th-century Silicon Valley and spread globally: pay partly in equity.

Employee equity:

• Substitutes for cash compensation during the cash-constrained early years.
• Aligns incentives — employees become economic owners and gain from the company's success.
• Retains talent through vesting schedules that reward staying with the company.
• Recruits talent competitively against larger employers paying higher cash.

The vehicle for delivering employee equity is the option pool — a reserve of shares set aside for grants. The pool typically holds 10–20% of fully diluted shares at a mature company; the percentage is refreshed at each priced funding round.

Individual grants come in several forms, varying by jurisdiction and seniority. The rest of this lesson examines the structures, the tax considerations that shape them, and the international variations on the basic option-grant model.

An employee stock option grants the right to buy a share at the strike price (or exercise price), regardless of the current market price.

For tax purposes, the strike price must be at or above the fair market value (FMV) of common stock at the date of grant. Below-FMV strikes are treated as deferred compensation under IRS Section 409A (in the US), with severe tax consequences for the employee.

Private companies do not have public market prices for their common stock. They establish FMV through a 409A valuation — a third-party appraisal conducted annually (or after any material event like a funding round). The 409A valuation typically uses one or more of:

• Income approach — discounted cash flow projections.
• Market approach — comparable public-company multiples adjusted for size, growth, profitability.
• Asset approach — fair value of assets (relevant mainly for very early-stage or asset-heavy companies).

The resulting common-stock FMV is typically substantially below the preferred-stock price from the most recent priced round. The difference reflects:

• Liquidation preferences that benefit preferred over common.
• Lack of marketability (common has no public market until IPO).
• Voting and control rights held by preferred.
• Other preferred privileges (dividend rights, anti-dilution).

A typical common-to-preferred ratio for an early-stage company is 0.20–0.40, meaning common is valued at 20–40% of the preferred-round price per share. At later stages (closer to IPO), the ratio rises toward 0.80–1.0.

The consequence for option grants: the strike price for options granted just after a funding round is typically a small fraction of the preferred-round price. This is why employees holding options in successful startups can realize substantial economic value at exit — they bought common at common's FMV, but the preferred (which they convert to or share with at sale) is worth much more.

US tax law recognizes two main categories of stock options.

Incentive Stock Options (ISOs). Special tax treatment available to employees only (not contractors or directors). Up to $100K of ISOs (measured by FMV at grant) can vest in any one year; excess automatically becomes NSO.

• At grant: no tax.
• At exercise: no regular income tax. The spread between FMV at exercise and strike price is added to alternative minimum tax (AMT) calculation — can trigger AMT for the employee.
• At sale: if the shares are held >1 year from exercise and >2 years from grant, the entire gain (from strike to sale price) is long-term capital gains (preferred US tax treatment, currently topping out at 20% federal). Otherwise, the spread at exercise is ordinary income.

Non-qualified Stock Options (NSOs). No special tax status. Granted to anyone (employees, contractors, directors).

• At grant: no tax.
• At exercise: the spread between FMV at exercise and strike is ordinary income (taxed at marginal rates) and subject to payroll tax (Medicare, Social Security up to limit).
• At sale: the additional gain (above FMV at exercise) is capital gain — long-term if held >1 year from exercise.

The ISO tax advantage:

• The exercise spread avoids ordinary income tax (subject to AMT consideration).
• The entire gain from strike to sale can be long-term capital gain.

The ISO disadvantage:

• AMT exposure at exercise — employees who exercise ISOs while the stock is illiquid and then watch the stock fall can owe substantial AMT on a paper gain they can't realize. The 2008–2010 crisis and 2022–2023 startup correction both produced cases where employees paid AMT on options whose value subsequently disappeared.
• $100K annual vesting limit (above this, automatic NSO treatment).
• Holding-period requirements bind for the favorable treatment.

Some option grants permit early exercise — the holder can exercise before the option fully vests, in which case the unvested portion is held as restricted stock subject to repurchase if the holder leaves.

The combination of early exercise and an 83(b) election can be tax-advantageous.

The 83(b) election. A US tax election filed within 30 days of receiving restricted stock (including stock from early-exercise of unvested options). The election causes the holder to pay tax on the value of the stock at acquisition (which is typically near the strike price if exercised early at low FMV) rather than at vesting (when FMV may be much higher).

The benefit:

• Tax base is locked in at the low early-exercise price.
• All subsequent appreciation is capital gain (long-term after 1+ year).
• AMT exposure for ISOs is minimized because the spread at exercise is small.

The risk:

• If the holder leaves before vesting, the unvested shares are repurchased — but the 83(b) tax was already paid on shares the holder no longer has.
• If the company fails, the early-exercise cash is lost.

The practical pattern: an early employee who joins right after a funding round (when common FMV is low) and early-exercises with an 83(b) can lock in long-term capital-gains treatment on the entire grant, at a small upfront cost in option-exercise cash and AMT.

Late employees joining at higher FMV face a larger upfront cost and AMT bill for early exercise, making it less attractive. The structure of who has the most to gain from early exercise mirrors the company's hiring history.

Restricted Stock Units (RSUs) are a different equity vehicle. An RSU is a promise of shares delivered at vesting. There is no exercise price and no exercise step.

• At grant: no tax.
• At vesting: the FMV of the vested shares is ordinary income to the employee. The company typically withholds for taxes by selling some shares (sell-to-cover) at the time of vesting.
• At sale: additional gain above FMV at vesting is capital gain (long-term after 1+ year from vesting).

RSUs vs options trade-off:

• RSUs always have value at vesting (as long as the stock has any value). Options are worthless if the stock drops below strike.
• RSUs do not require cash to exercise. Options require the employee to pay the strike price at exercise.
• RSUs have less upside leverage. An option to buy 1000 shares at $1 captures all upside above$1; an RSU for 100 shares captures only the value of the 100 shares.
• RSUs accelerate ordinary income to vesting; options can defer or convert to capital gains.

Private startups typically grant options because the company's value is uncertain, the cash required to exercise is small, and the leverage is large. Public companies typically grant RSUs because the stock has known value, vesting is the natural recognition event, and the cash-payment problem disappears in a liquid market.

Late-stage private companies sometimes switch to RSUs as IPO approaches. Double-trigger RSUs — units that vest on time and on a liquidity event (IPO or acquisition) — are a hybrid used to defer the tax event past the typically-illiquid private stage.

Many jurisdictions have created tax-advantaged employee equity schemes targeted at startup hiring.

BSPCE (Bons de Souscription de Parts de Créateur d'Entreprise, France). Similar to ISOs in spirit. Available to employees and directors of French companies under conditions on company age, size, and ownership. The tax benefits include:

• No tax at grant.
• No tax at exercise.
• At sale: the gain (sale price minus strike) is taxed at a favorable rate (currently 12.8% to 30% depending on holding period and the holder's tax bracket), substantially lower than ordinary income rates.

BSPCE is restricted to companies under 15 years old, with majority private ownership, meeting specific French regulatory conditions. The structure has been a key tool for the French startup ecosystem's compensation packages.

EMI (Enterprise Management Incentives, UK). A tax-advantaged option scheme available to qualifying small-to-medium UK companies (gross assets under £30M and fewer than 250 employees at grant).

• No income tax or NI at grant or exercise (provided strike ≥ FMV at grant).
• At sale: gain is taxed at the favorable Business Asset Disposal Relief rate (10% on the first £1M of qualifying lifetime gains).

The UK has additional schemes (CSOP, SAYE, SIP) for different scenarios. EMI is the dominant venture-stage option scheme.

Other jurisdictions. Germany has VSOP (virtual stock option program) commonly used; Spain has ISO-like structures; the Netherlands and Sweden have specific schemes. Each has its own regulatory eligibility, tax treatment, and administrative requirements.

Multi-country companies face the structural challenge of granting compensation that is incentive-aligned across jurisdictions despite the different tax treatments. Standard approaches:

• Use the local instrument where possible (BSPCE in France, EMI in UK, ISO in US for US employees).
• Fall back to NSO-equivalent or virtual equity for jurisdictions without favorable schemes.
• Document the grant economics so employees in different jurisdictions can compare effective compensation.

The structural lesson: employee equity is a tax-driven negotiation as much as an incentive-driven one. The headline grant size matters; so does the tax-after-tax value to each employee.

Vesting (introduced in lesson 1) is the schedule by which options become exercisable. The 4-year vesting + 1-year cliff structure is near-universal at venture-stage companies.

Acceleration modifies vesting under specific conditions:

• Single-trigger: vesting accelerates on a change of control alone (e.g., acquisition closes).
• Double-trigger: vesting accelerates on change of control and subsequent involuntary termination within a defined window (typically 12 months).

Double-trigger is the more common acceleration for executive grants. It encourages executives to stay through the transition while protecting them from acquirer-driven dismissal.

Refresh grants are additional grants given to existing employees, often at the end of the initial 4-year vesting period, to maintain incentive alignment. A senior engineer who fully vested their initial grant may receive a refresh grant of 25–50% of the initial size to start a new 4-year vesting cycle. The refresh strike price is set at the then-current FMV, which is typically much higher than the initial strike — so the employee retains exposure to additional upside on the refreshed shares.

The strike-price ceiling problem. A long-tenured employee at a fast-growing company has options with very different strike prices: low for early grants, much higher for refresh grants. If the company's stock falls (down round, market correction), refresh-grant options can go underwater while early-grant options remain in-the-money. The employee's effective vesting equity drops sharply on the refresh portion. This dynamic was visible in the 2022–2024 tech correction: experienced employees at decacorn startups saw refresh grants fall below strike while their original grants retained value.

The structural lesson: employee equity is a compounding instrument over an employee's tenure. The initial grant matters; refresh grants matter; the strike-price trajectory across them shapes the realized economic value far more than the headline grant numbers suggest.

Three structural points for the cursus.

• Employee equity is shaped by tax law. ISOs vs NSOs in the US, BSPCE in France, EMI in the UK — the structures differ because tax authorities have created (or not created) preferential schemes. A grant that is tax-efficient in one jurisdiction is not in another.
• The strike price is set by the 409A valuation, which is much lower than the preferred-round price. This is what makes employee options valuable: they buy common stock at common's FMV, while preferred and the exit value sit much higher.
• Vesting + refresh grants + the strike-price trajectory determine realized value. Headline grant sizes are headlines; the realized after-tax value depends on when grants were issued, what the strike was, when they vested, and how the company's value evolved during vesting.

The last lesson in the cursus moves from these incentive mechanics to the exit math — the waterfalls that determine, at the moment of sale or IPO, how the total proceeds are divided among preferred, common, options, and outstanding convertibles.