ISO vs. NSO: How They Differ

If you’ve been granted employee stock options by a private company, you hold a stake in its future success. Stock options give you the right — though not the obligation — to purchase company shares at a set price in the future, known as the “strike price.” If the business grows and its stock appreciates, you can “exercise” your options (buy the shares) at your lower strike price and potentially sell them later at a profit.

Not all options work the same way, however. In the United States, there are two primary categories: incentive stock options (ISOs) and non-qualified stock options (NSOs) . They differ chiefly in who may receive them, how flexible they are, and how they’re taxed. Grasping these distinctions is essential to making smart decisions about the equity you’ve been granted.

What Are Incentive Stock Options (ISOs)?

Incentive stock options may only be granted to direct employees of a company. These options carry specific tax advantages under U.S. law, but only if both the company and you follow certain rules. The primary benefit of ISOs is that you generally don’t owe taxes when you exercise them. Instead, taxes come due later, when you sell the shares. You may also hear ISOs referred to as “qualified incentive stock options” or “statutory stock options.”

What Are Non-Qualified Stock Options (NSOs)?

Non-qualified stock options (NSOs or NQs) come with fewer restrictions than ISOs. Companies can grant NSOs to anyone who works with or for the business — including employees, contractors, company directors, and even vendors.

However, NSOs don’t receive the same tax breaks that ISOs offer. When you exercise your NSOs and buy your shares, you owe regular income tax on the difference between the price you pay for the shares (your “strike price”) and what the shares are actually worth at that moment (the 409A valuation).

Requirements of ISOs

To unlock the tax advantages of ISOs, both you and your company must follow certain rules:

  • A company may only grant ISOs to employees.
  • The business must price the ISOs at their “fair market value,” as determined by the business’s 409A valuation.
  • In any given calendar year, an employee can’t exercise more than $100,000-worth of ISOs, based on the company’s fair market value. Any amount beyond that threshold is treated like NSOs instead.
  • Employees must exercise ISOs within three months of leaving the company, or they’ll be treated as NSOs.
  • ISOs can’t be transferred to someone else, unless the original employee dies. If a company permits stock options to be given to another person, and an ISO is transferred during the employee’s lifetime, it will be treated as an NSO.
  • You must exercise your ISOs within 10 years of the grant date.
  • You must hold your ISOs for more than two years after the grant date before you exercise them, and you must keep the shares for more than one year before selling. If you don’t meet these two criteria, your options will be treated as NSOs.

How ISOs Work

ISOs are usually granted on a vesting schedule, meaning you earn the right to exercise them over time, starting from the day you first receive them. You can only exercise your options after they have vested.

If your ISOs follow all the rules in the “Requirements of ISOs” section above, you’ll unlock their tax benefits:

When you exercise your options: The on-paper profit you make — the difference between your strike price and the shares’ fair market value — won’t be taxed like your regular income or payroll taxes. Instead, it may be subject to a special tax called the Alternative Minimum Tax (AMT). The AMT is a tax system that ensures wealthier individuals pay at least a basic amount of tax, even if they have a lot of tax breaks.

When you sell your shares: If you kept your ISOs for more than two years after their grant date before exercising them, plus you held those shares for more than one year before selling, you’ll pay long-term capital gains tax on the difference between the fair market value on the exercise date and the sale price. This is less than you would owe if your ISOs were subject to short-term capital gains tax.

Remember: you can sell your ISOs whenever you like after they’ve vested and been exercised, but if you don’t hold your options or shares for the right length of time, they’ll be taxed like NSOs.

How NSOs Work

NSOs are also usually given out on a vesting schedule, so you’ll earn the right to exercise them over time. Like ISOs, you can only exercise your options after they have vested.

When you exercise your options: You’ll pay ordinary income tax on any gains you make on the difference between your strike price and the fair market value of the shares at the date you exercise them.

When you sell your shares: The difference between the fair market value on the exercise date and the sale price will be treated as a capital gain. You’ll be taxed at the short-term capital gains rate if you hold your shares for less than a year after exercising. You’ll be taxed at the long-term capital gain rate if you hold them for more than a year.

Purposes of ISOs and NSOs

ISOs and NSOs are used for different reasons. Because ISOs can save employees money on taxes, companies often set aside a portion of their stock (called an employee option pool) specifically for these options, which are given to key hires to encourage them to stay with the organization.

NSOs can be useful for rewarding staff and non-employees — such as contractors and service providers — with equity in the company. These options can be used in addition to or instead of paying them directly.

Understand What Kind of Private Stock Option You Hold

The type of stock options you have plays a big role in how you should plan to manage them. Because the tax rules are complex and can significantly affect how much money you actually keep, it’s always a good idea to talk to a financial advisor or a tax professional who specializes in stocks. They can help you understand your specific situation, calculate potential tax bills, and choose the best strategy for your financial goals. Knowing these differences will help you make the most of your options.