An employee equity program is a compensation arrangement in which a company pays part of your wages in ownership of the business itself, usually through company stock or the right to acquire it later. Instead of handing you cash alone, the employer ties a portion of your pay to the company’s long-term value, so if the company grows, your compensation grows with it. These programs are especially common in technology and other high-growth industries, where they let employers attract talent that might otherwise command higher base salaries. The pieces you need to understand are the type of award you’re being given, the vesting schedule attached to it, the tax treatment that applies when the award pays out, and (if the employer is private) the practical question of how and when you’ll ever turn the equity into cash.
The Types of Awards You’re Likely to See
Most employee equity falls into one of four categories, each with different mechanics and risk.
Restricted Stock Units
An RSU is the company’s promise to deliver shares at a future date, once a vesting requirement is met. You don’t pay anything to receive them. Each unit converts into one share when the restriction lifts, and the value to you is simply the market price on the vesting date. Because that value is whatever the stock is worth (not a spread above some strike price), RSUs always have some value as long as the stock does. That built-in floor is why RSUs are the most common form of equity at large public companies.
Before vesting, you don’t own shares and have no voting rights. Some companies attach “dividend equivalents” to unvested RSUs, paying you cash that mirrors dividends paid to real shareholders; those payments are taxed as ordinary compensation, not qualified dividends.
Stock Options
A stock option gives you the right to buy a set number of shares at a locked-in price, called the strike price or exercise price. The option becomes profitable only when the market price climbs above the strike; the gap between the two is the spread. If the market price never exceeds the strike, the option is “underwater” and worth nothing. Options come in two tax flavors.
Incentive Stock Options (ISOs) are reserved for employees and offer potential tax advantages, but only if the grant meets the requirements of Internal Revenue Code Section 422. The strike price must be at least the fair market value on the grant date, the option can’t be exercisable more than ten years after grant, and it can only be transferred by will or inheritance. There is also an annual ceiling: if the total fair market value of stock (measured at grant) first becoming exercisable in any calendar year exceeds $100,000, the excess is treated as non-qualified options.
Some companies permit “early exercise,” letting you buy shares before the options vest. Early-exercised shares stay on the original vesting schedule, and the company can repurchase unvested shares if you leave. Early exercise is most useful at startups where the stock price is still low, because it opens the door to the Section 83(b) election described below.
Non-Qualified Stock Options (NSOs) are more flexible. Companies can grant them to employees, directors, advisors, and independent contractors, and they don’t have to satisfy Section 422. The strike price is usually set at fair market value on the grant date as a design choice, though Section 409A imposes its own pricing rules on deferred compensation. The tradeoff for the flexibility is weaker tax treatment, which is covered below.
Employee Stock Purchase Plans
An ESPP lets you buy company stock at a discount through payroll deductions. Under a qualified plan governed by Section 423, you contribute after-tax dollars during an offering period, then use the accumulated funds to purchase shares at a discount of up to 15% off the market price. Contributions are capped: your right to purchase stock under all of an employer’s ESPPs cannot accrue at a rate exceeding $25,000 in fair market value per calendar year.
The feature that makes qualified ESPPs so valuable is the “look-back provision.” The statute allows the purchase price to be based on the lower of the stock price at the beginning or end of the offering period, with the discount applied to that lower price. If the stock rises during the offering period, you’re effectively buying at a discount off a price that was already below market.
Vesting: What You Actually Get to Keep
Vesting is the mechanism that ties the equity to your continued employment. Until it vests, the award is a contingent promise, and unvested equity is almost always forfeited if you leave.
- Time-based vesting releases shares on a fixed schedule, such as 25% per year over four years.
- Cliff vesting releases nothing until a single milestone (often one year of service), then a chunk vests at once. Many four-year schedules combine a one-year cliff with monthly or quarterly vesting afterward.
- Performance-based vesting releases shares when the company hits specific targets like revenue goals or product milestones. This is more common for executives and senior hires.
If the company is acquired, your unvested equity doesn’t automatically become yours; what happens depends on the agreement. Single-trigger acceleration vests everything on the acquisition itself and is relatively rare outside founder-level grants. Double-trigger acceleration requires both the acquisition and an involuntary termination (or resignation for good reason, such as a pay cut or forced relocation) within a window afterward, usually nine to eighteen months. Double-trigger is more common because acquirers generally want the team to stay.
How Each Award Is Taxed
Taxes are where most people get tripped up. The type of award, the timing of your decisions, and how long you hold the shares all interact to decide whether you pay ordinary income rates or long-term capital gains rates.
RSUs
Nothing happens at grant. When RSUs vest and shares hit your account, the full market value counts as ordinary income, and the employer withholds taxes, usually by holding back a portion of the vesting shares. Any gain or loss after vesting is a capital gain or loss, taxed at long-term rates if you hold the shares more than a year past the vesting date.
ISOs
ISOs get preferential treatment if you follow the rules precisely. No regular income tax is owed when you receive or exercise the option. The catch is the Alternative Minimum Tax: the spread at exercise is an AMT adjustment item, which can trigger an AMT bill even though no regular tax is due on the exercise.
To secure long-term capital gains treatment on the eventual sale, you must satisfy two holding periods: at least two years from the grant date and at least one year from the exercise date. A sale meeting both is a “qualifying disposition,” and the entire gain (sale price minus strike price) is taxed at capital gains rates. Sell earlier and it becomes a “disqualifying disposition”: the spread at exercise is reclassified as ordinary income, wiping out most of the ISO advantage.
NSOs
NSO taxation is simpler but less favorable. Nothing is taxed at grant. When you exercise, the spread between the strike price and the current market value is ordinary income, reported on your W-2 and subject to federal and state income taxes plus Social Security and Medicare. Any additional gain after exercise is a capital gain, taxed at long-term rates if you hold for more than a year.
ESPPs
For a qualified ESPP, the discount isn’t taxed at purchase. The tax event happens at sale. If you sell after holding the shares at least two years from the offering date and one year from the purchase date, you report the lesser of the actual gain or the discount amount as ordinary income, and the rest is long-term capital gains. The statute specifically provides that no withholding is required on this ordinary income component. If you sell earlier, the discount portion is ordinary income regardless of whether the stock went up or down after purchase.
The Section 83(b) Election
This is a narrow but high-stakes tool, mostly for startup employees who receive restricted stock or early-exercise their options. Under the default rules in Section 83, you’re taxed when the restriction lifts (when the stock vests), based on the value at that point. If you joined when shares were worth $0.10 and they’re worth $50 at vesting, you owe income tax on $49.90 per share.
An 83(b) election flips the timing. You choose to be taxed immediately at transfer, based on the stock’s current value. Filing when shares are worth $0.10 means paying tax on $0.10 per share (minus whatever you paid). All future appreciation is then capital gains when you sell.
The deadline is strict: the election must be filed with the IRS within 30 days of the transfer date. Miss that window and the election is gone permanently. There is also real downside: if you file the election and then forfeit the stock by leaving before it vests, you don’t get a refund on taxes already paid. The election makes the most sense when the current value is low and you believe it will appreciate significantly.
Private Company Equity Is a Different Problem
Equity at a private company has complications public-company employees don’t face. The biggest is liquidity. You can’t simply sell on an exchange; turning the equity into cash usually requires an IPO, an acquisition, or a company-sponsored secondary sale.
Private companies also have no public market price to set a strike price against, so they obtain an independent valuation to determine fair market value. This is a “409A valuation,” named for the tax code section that governs nonqualified deferred compensation. Getting it wrong is painful for the employee: if the strike price is below fair market value, the options can be treated as deferred compensation that violates Section 409A, making the deferred compensation immediately taxable with a 20% additional tax plus interest on top. The IRS provides a safe harbor: a valuation by a qualified independent appraiser is presumed reasonable for 12 months unless a material event (like a new funding round) changes the picture. Most startups refresh the 409A annually or after each significant financing event.
If you have vested options at a private company, exercising means spending real cash on shares you can’t immediately sell. The tax bill arrives on schedule regardless. ISOs can trigger AMT; NSOs produce ordinary income on the spread. In both cases you can be paying tax on value you can’t yet access, and employees have been caught by six-figure bills on equity they couldn’t sell for years. Before exercising, add up the total cost (strike price plus taxes) and confirm you can absorb it.
What Happens When You Leave
This is where equity compensation gets unforgiving. Unvested equity is almost always forfeited on departure. The sharper question is what happens to your vested options.
Most option agreements give departing employees a post-termination exercise period, and the most common window is 90 days. Miss it and your vested options expire worthless. For ISOs, the tax code imposes its own constraint: to keep ISO treatment, you must exercise within three months of leaving. Exercise later and the options are taxed as NSOs.
The 90-day clock creates a hard decision at private companies, where exercising may mean thousands of dollars spent on shares you can’t sell, with no certainty the company will ever have a liquidity event. Some employers have moved to longer post-termination exercise windows of a year or more, but the 90-day standard remains the majority. Check this term in your equity agreement before you accept a job.
For RSUs, the picture is simpler: unvested RSUs are forfeited, and shares that already vested and were delivered to you remain yours.
Dilution and Reading an Offer
Your equity represents a slice of the company, and that slice can shrink. Whenever the company issues new shares (through a funding round, new employee grants, or option exercises), the total outstanding grows, and your ownership as a fraction of the whole gets smaller even though your share count hasn’t changed. That’s dilution.
Dilution isn’t automatically bad. If a round doubles the company’s value while adding 20% more shares, your smaller percentage is worth more in absolute terms. But at startups that go through multiple rounds, early employees can see their ownership percentage shrink substantially by the time an exit arrives. When evaluating an offer, the raw number of shares matters far less than what percentage of the fully diluted share count those shares represent, and what the company’s current valuation implies each share is worth.