Stock compensation—options, RSUs, and ESPP—can represent a significant portion of your total pay, especially at tech companies. Understanding how each type works and is taxed can save you tens of thousands of dollars.
Table of Contents
Types of Stock Compensation at a Glance
| Type | What You Get | Cost to You | Taxed When | Tax Rate |
|---|---|---|---|---|
| ISO (Incentive Stock Options) | Right to buy at exercise price | Exercise price × shares | At sale (if you hold) | Capital gains |
| NSO (Non-Qualified Stock Options) | Right to buy at exercise price | Exercise price × shares | At exercise (spread) | Ordinary income |
| RSU (Restricted Stock Units) | Actual shares after vesting | $0 | At vesting | Ordinary income |
| ESPP (Employee Stock Purchase Plan) | Shares at 10-15% discount | Discounted price | At sale | Varies |
RSUs (Restricted Stock Units)
How RSUs Work
- Company grants you a number of RSUs (e.g., 1,000 RSUs)
- RSUs vest over time (typically 4-year schedule)
- At vesting, you receive shares and owe ordinary income tax
- You can sell immediately or hold for potential capital gains
Typical Vesting Schedules
| Schedule | Year 1 | Year 2 | Year 3 | Year 4 |
|---|---|---|---|---|
| 4-year annual | 25% | 25% | 25% | 25% |
| 4-year with 1-year cliff | 25% | 25% | 25% | 25% |
| 4-year quarterly (after cliff) | 6.25%/quarter | 6.25%/quarter | 6.25%/quarter | 6.25%/quarter |
| 3-year annual | 33% | 33% | 34% | — |
RSU Tax Example
Grant: 1,000 RSUs. Stock price at vesting: $150/share.
| Event | Shares | Value | Tax |
|---|---|---|---|
| Year 1 vest (250 shares) | 250 | $37,500 | Ordinary income tax (~$9,000 at 24%) |
| Year 2 vest (250 shares) | 250 | $37,500 | Ordinary income tax (~$9,000 at 24%) |
| Sell 500 shares at $200 | 500 | $100,000 | Capital gains on $25,000 gain ($50 × 500) |
Total grant value: $150,000 at vesting + $25,000 in capital gains = $175,000 pre-tax
Stock Options (ISOs vs. NSOs)
Key Differences
| Feature | ISO | NSO |
|---|---|---|
| Tax at exercise | No ordinary income tax* | Ordinary income on spread |
| Tax at sale | Long-term capital gains (if qualified) | Capital gains on post-exercise gain |
| AMT impact | May trigger AMT | No AMT impact |
| Holding requirement | 1 year after exercise + 2 years after grant | None |
| Eligibility | Employees only | Employees, contractors, advisors |
| Annual limit | $100,000 vesting per year (ISO treatment) | No limit |
*ISOs may trigger Alternative Minimum Tax (AMT) at exercise.
Stock Option Tax Example
Grant: 1,000 options. Exercise price: $50. Stock price at exercise: $150. Stock price at sale: $200.
| Event | ISO | NSO |
|---|---|---|
| At exercise | No ordinary tax (AMT on $100K spread) | $100,000 taxed as ordinary income |
| At sale ($200) | $150,000 gain taxed as LTCG (if qualified) | $50,000 gain taxed as capital gains |
| Best-case tax rate | 15-20% on full $150K gain | 24-37% on $100K + 15-20% on $50K |
| Tax amount (estimated) | $22,500-$30,000 | $30,000-$44,000 |
ISOs can save $10,000-$15,000 in taxes in this example—but require holding for 1+ year after exercise.
ESPP (Employee Stock Purchase Plan)
| Feature | Typical ESPP |
|---|---|
| Discount | 10-15% off stock price |
| Contribution limit | Up to $25,000/year (at purchase price) |
| Offering period | 6 months (common) or up to 27 months |
| Lookback provision | Purchase at lower of start or end price minus discount |
| Payroll deduction | 1-15% of paycheck |
ESPP Return Example (15% Discount, No Lookback)
| Scenario | Your Cost | Share Value | Instant Gain | Return |
|---|---|---|---|---|
| Stock flat ($100→$100) | $85 | $100 | $15 | 17.6% |
| Stock up 10% ($100→$110) | $85 | $110 | $25 | 29.4% |
| Stock down 10% ($100→$90) | $76.50 | $90 | $13.50 | 17.6% |
ESPP with a 15% discount is essentially a guaranteed 15-30%+ return if you sell immediately after purchase.
Strategies for Stock Compensation
Concentration Risk
| Company Stock % of Net Worth | Risk Level | Action |
|---|---|---|
| Under 10% | Low | Hold if you’re bullish |
| 10-25% | Moderate | Consider selling some at vesting |
| 25-50% | High | Sell most above 25% threshold |
| Over 50% | Very high | Diversify aggressively |
Rule of Thumb
Don’t let any single stock, including your employer, exceed 10-20% of your total investment portfolio. Your income already depends on the company—your investments shouldn’t too.
The Bottom Line
RSUs are the simplest form of equity comp—you receive shares and owe taxes at vesting. Stock options can be more tax-efficient (especially ISOs) but are worthless if the stock falls below the exercise price. Always participate in ESPP if offered at a 15% discount—it’s one of the best risk-adjusted returns available. Regardless of type, diversify beyond your company stock to avoid concentration risk.
