Stock Options vs Other Equity Types: ISOs, NSOs, RSUs, SARs, and More

"Equity compensation" is an umbrella term that covers several distinct instruments, each with different tax treatment, risk profiles, and mechanics. Stock options (ISOs and NSOs) are the most well-known type, but they are just one category. This guide covers every common equity compensation type, compares their tax treatment, and explains when companies use each one.

The Equity Compensation Landscape

There are six main types of equity compensation:

1. Incentive Stock Options (ISOs) --- Tax-advantaged options for employees
2. Non-Qualified Stock Options (NSOs) --- Standard options for anyone
3. Restricted Stock Units (RSUs) --- Promised shares that vest over time
4. Restricted Stock Awards (RSAs) --- Actual shares granted immediately (subject to forfeiture)
5. Stock Appreciation Rights (SARs) --- Cash or stock equal to appreciation
6. Phantom Equity / Profits Interests --- Synthetic equity, no actual shares

Master Comparison Table

Stock Options: ISOs and NSOs

Stock options give you the right to buy company shares at a fixed price (the strike price). The value is the spread between the current market price and your strike price.

ISOs (Incentive Stock Options)

• Employee-only --- contractors and board members cannot receive ISOs
• No regular income tax at exercise (but the spread is an AMT preference item)
• Long-term capital gains at sale if you hold 1 year from exercise AND 2 years from grant
• $100K annual limit on ISOs first exercisable in any year (excess treated as NSOs)
• See our detailed ISO vs NSO comparison

NSOs (Non-Qualified Stock Options)

• Available to anyone --- employees, contractors, advisors, board members
• Ordinary income at exercise on the full spread (appears on W-2 for employees, 1099 for contractors)
• Subject to FICA taxes (Social Security and Medicare) at exercise
• No annual limit on grant size
• Employer gets a tax deduction equal to the income recognized

For exercise timing strategies, see our guide on when to exercise stock options.

RSUs (Restricted Stock Units)

RSUs are a promise to deliver shares in the future when vesting conditions are met. They are not actual shares until they vest --- you have no voting rights and receive no dividends during the vesting period.

• No exercise cost --- shares are delivered free at vest
• Taxed as ordinary income at vest on the full FMV
• Simple and predictable --- vesting is automatic, no decisions required
• Always have value (unlike options, which can be underwater)
• The dominant equity type at public companies
• See our RSU tax guide for full details

Restricted Stock Awards (RSAs)

RSAs are actual shares granted immediately, but subject to a vesting schedule and forfeiture risk. If you leave before vesting, you forfeit unvested shares.

The key difference from RSUs: you own the shares from day one. This means:

• Voting rights from the grant date
• Dividend eligibility (if the company pays dividends)
• Eligible for 83(b) election --- this is the big advantage

The 83(b) Election Advantage

With a restricted stock award, you can file an 83(b) election within 30 days of the grant to pay ordinary income tax on the current FMV instead of waiting until vesting. If the stock appreciates significantly, this converts all future appreciation from ordinary income to long-term capital gains.

Example: You receive 10,000 restricted shares at $1 FMV. Without 83(b), if shares are worth $50 at vesting, you owe ordinary income tax on $500,000. With 83(b), you pay ordinary income tax on $10,000 at grant and the $490,000 appreciation is taxed as LTCG (15-20%).

See our 83(b) election guide and use our 83(b) calculator for your specific scenario.

Stock Appreciation Rights (SARs)

SARs give you the right to receive the appreciation in stock value over a base price, without actually buying shares. They work like stock options but settle in cash or stock at exercise --- no exercise cost required.

• No purchase required --- you receive the spread directly
• Taxed as ordinary income at exercise (like NSOs)
• Common in companies that want to provide option-like incentives without diluting shares
• Cash-settled SARs do not create actual shareholders (useful for private companies that want to limit the cap table)

Phantom Equity and Profits Interests

Phantom Equity

Phantom equity is a contractual agreement to pay an employee a bonus tied to the company's stock value. No actual shares are issued. It is used by companies that do not want to (or cannot) issue real equity.

• Taxed as ordinary income when paid out
• No shareholder rights (no voting, no dividends, no ownership)
• Common in LLCs, partnerships, and companies with complex cap tables
• Subject to Section 409A deferred compensation rules (strict timing requirements)

Profits Interests

A form of equity unique to LLCs and partnerships. A profits interest gives you a share of future appreciation (not existing value). If structured correctly:

• No tax at grant (the interest has zero current value)
• Capital gains treatment on eventual sale
• Must receive only future profits --- not existing equity value
• Common at private equity firms, venture-backed LLCs, real estate partnerships

Equity by Company Stage

Evaluating Equity in a Job Offer: 10-Item Checklist

Before accepting any equity offer, get answers to these ten questions. The number of shares alone is meaningless without context:

1. Type of equity. Is it an ISO, NSO, RSU, restricted stock, or something else? This determines every tax rule that applies to you.
2. Number of shares or units. This is the headline number, but it means nothing without #5 below. 10,000 shares of a company with 10M outstanding is 0.1%; 10,000 shares of a company with 1B outstanding is 0.001%.
3. Strike price or current FMV. For options, the strike price is your entry point. For RSUs, the current FMV is the value per share at vesting. Ask for the most recent 409A valuation.
4. Vesting schedule. The standard is 4 years with a 1-year cliff. Some companies offer 3-year schedules or monthly vesting after the cliff. Shorter cliff = less risk of walking away with nothing.
5. Total shares outstanding (fully diluted). This lets you calculate your ownership percentage. Request this explicitly --- companies sometimes avoid sharing it.
6. Latest 409A valuation date and trend. A recent valuation (within 6 months) is more reliable. Ask whether the 409A has been increasing, stable, or declining --- this signals company trajectory.
7. Exercise window after departure. The standard is 90 days, which can create a cash crunch. Some companies offer 5-10 year exercise windows. This single term can be worth tens of thousands of dollars.
8. Acceleration provisions. Single trigger (acceleration on acquisition) vs double trigger (acceleration requires acquisition + termination). Double trigger is standard; single trigger is significantly more employee-friendly.
9. Transfer restrictions and right of first refusal. Can you sell shares on a secondary market (e.g., Forge, Carta) before an IPO? Many private companies retain a right of first refusal, limiting your ability to generate liquidity.
10. Liquidation preferences. In an acquisition, preferred shareholders (investors) typically get paid before common shareholders (employees). If the company raised $100M in preferred stock and sells for $120M, employees split only $20M. This matters enormously for startup equity valuation.

Use our equity compensation calculator to model the financial impact of any offer.

Tax Treatment Summary Table

Every equity type follows different tax rules at each stage of its lifecycle. This table summarizes the treatment for each:

Negotiating Equity in a Job Offer

Not everything is negotiable --- but more than you think. Here is what you can and cannot change:

Negotiable terms:

• Number of shares/units. This is the most common negotiation point. Companies expect you to negotiate equity size.
• Vesting schedule length. Some companies will shorten from 4 years to 3, or remove the cliff entirely for senior hires.
• Cliff length. You can ask to reduce the cliff from 12 months to 6, or eliminate it (monthly vesting from day one).
• Exercise window post-departure. This is increasingly negotiable, especially at startups competing for talent. Ask for 5-10 years.
• Acceleration triggers. Double-trigger acceleration (vesting accelerates if the company is acquired AND you are terminated) can sometimes be negotiated for executive roles.

Not negotiable:

• Option type (ISO vs NSO). The company decides based on IRS limits and their equity plan. ISOs are only available to employees and subject to the $100K annual limit --- shares exceeding this automatically convert to NSOs.
• Strike price. Set by the 409A valuation at grant. The company cannot legally give you a below-market strike price.
• RSU delivery mechanism. Whether shares are settled in stock or cash, and whether sell-to-cover or net settlement is used, is company policy.

Tip: If offered NSOs, ask whether ISOs are available. The company may have room under the $100K annual limit and may simply default to NSOs for simplicity.

Frequently Asked Questions

Which equity type is best?

There is no single best type. ISOs offer the best tax treatment for employees at early-stage companies. RSUs offer the most predictable value at public companies. The best type depends on company stage, your risk tolerance, your cash reserves, and your tax situation. Use our equity compensation calculator to model your scenario.

Can I receive multiple types of equity from the same company?

Yes. It is common to hold ISOs from an early grant, NSOs (from ISO grants that exceeded the $100K limit), and RSUs from a later refresh grant --- all from the same company. Each type follows its own tax rules independently.

What is the most tax-efficient equity type?

ISOs with a qualifying disposition offer the lowest tax rate (long-term capital gains). However, this requires cash to exercise, tolerance for AMT, and willingness to hold shares through the qualifying period. For most people at public companies, RSUs with immediate sale and reinvestment into a diversified portfolio produces the best risk-adjusted outcome.

Do contractors always get NSOs?

Contractors receive NSOs (never ISOs, which are employee-only). Some companies grant RSUs to long-term contractors, but this is less common. Contractors may also receive SARs or phantom equity depending on the company structure.

What should I ask about equity in a job offer?

Ask for: (1) the type of equity (ISO, NSO, RSU, RSA), (2) number of shares or units, (3) strike price (for options) or current FMV (for RSUs), (4) vesting schedule and cliff, (5) total shares outstanding (to calculate your ownership percentage), (6) latest 409A valuation date, and (7) exercise window after departure.