ISO vs NSO: Understanding Stock Option Types

What Are Stock Options?

Stock options give you the right to buy company stock at a set price (the "strike price" or "exercise price"). If the stock price goes up, you can buy shares below market value.

ISO vs NSO: Quick Comparison

Understanding ISOs

Incentive Stock Options (ISOs) have special tax treatment that can save you money - but with some catches.

ISO Tax Treatment

1. At grant: No tax
2. At exercise: No regular income tax, but the "spread" counts for AMT
3. At sale (qualified): All gains taxed as capital gains
4. At sale (disqualified): Spread taxed as ordinary income

ISO Qualifying Disposition

To get the favorable tax treatment, you must:

• Hold shares for 2+ years from grant date
• Hold shares for 1+ year from exercise date
• Not sell in the same year you exercise

The ISO $100k Rule

Only $100,000 worth of ISOs (based on exercise price) can vest in any calendar year. Options above this limit automatically become NSOs.

Understanding NSOs

Non-Qualified Stock Options (NSOs) are more straightforward but less tax-advantaged.

NSO Tax Treatment

1. At grant: No tax
2. At exercise: The spread (market price - exercise price) is taxed as ordinary income
3. At sale: Any additional appreciation is taxed as capital gains

NSO Example

You have NSOs with a $10 strike price. When you exercise:

• Current stock price: $50
• Spread: $40 per share
• Tax treatment: $40 is ordinary income (subject to income tax + payroll taxes)

If you later sell at $60:

• Additional gain: $10 per share
• Tax treatment: $10 is capital gains

When ISOs Are Better

ISOs can be advantageous when:

• You can hold shares for the qualifying period
• The AMT hit is manageable
• You expect significant appreciation
• You're in a high income tax bracket

When NSOs Are Better

NSOs might be better when:

• You want to exercise and sell immediately
• You're a contractor (ISOs not available)
• The option grant exceeds the $100k limit
• You need certainty on tax treatment

Key Decisions to Make

1. When to Exercise

• Early exercise: Lock in lower strike price (if allowed)
• Wait until vested: Less risk but potentially higher taxes
• Just before expiration: Maximum time for appreciation

2. Whether to File an 83(b) Election

If you early exercise, an 83(b) election can start your capital gains clock early. This only applies to unvested shares.

3. Sell or Hold After Exercise

• Consider concentration risk
• Evaluate tax implications
• Think about your overall portfolio

Common Mistakes to Avoid

1. Letting options expire worthless: Mark your calendar
2. Ignoring AMT for ISOs: Can create unexpected tax bills
3. Not exercising before leaving: Usually only 90 days post-termination
4. Over-concentrating: Don't put all eggs in one basket