RSUs vs ISOs vs NSOs vs. ESPPs - How to Avoid the Biggest Equity Compensation Mistakes

RSUs vs ISOs vs NSOs vs ESPPs: if you work in tech or at a high growth startup, there is a good chance a big part of your pay is equity compensation, and each type is taxed differently. This article covers how each one works, how it is taxed, and where people tend to get caught.

How RSUs work and how they are taxed

Restricted stock units are the simplest form of equity and the standard at most public companies. The company grants you shares over time as long as you stay, which is called vesting.

When RSUs vest, the value of the shares counts as ordinary income. If 1,000 shares vest at $50 a share, $50,000 of income is added to your W2. Most companies sell some shares to cover taxes, typically withholding 22% for federal tax. If your actual bracket is 32%, 35%, or 37%, that will not be enough, and you might owe several thousand dollars when you file. That is why we often plan ahead for each vest.

Because RSUs are taxed at vesting and not at sale, there is also phantom income risk. If your shares vest at $100 and the stock falls to $60 by year end, you are still taxed on $100 a share. For many people, the sensible move is to sell vested shares gradually and diversify.

How ISOs are taxed and the holding period rules

Incentive stock options are common at private tech companies and startups. There is no tax at grant. For your profit to be taxed as long term capital gains, you need to hold the shares at least 1 year after exercise and 2 years after the original grant date. Those rates are typically much lower.

The AMT trap when you exercise ISOs

Say Sarah is granted 10,000 ISOs with a $1 strike price, and 3 years later the fair market value is $10 a share. If she exercises, the $9 per share difference, called the bargain element, is not taxed for regular income tax purposes, but it is added to her income under the Alternative Minimum Tax (AMT).

That is a $90,000 AMT adjustment. Depending on her other income, that could mean $20,000 to $25,000 of AMT with no cash from selling shares. If you do pay AMT, it is not always lost, because you can earn an AMT credit to offset taxes in future years.

Early exercise and the 83(b) election

Some companies let you exercise options before they vest. If you do that when the fair market value and strike price are basically the same, there is no meaningful spread. You then file an 83(b) election with the IRS within 30 days, which asks to be taxed now, when the shares are worth very little. If the company takes off, future growth is treated as capital gains. If it fails, you are out your exercise cost, so there is still risk.

Early stage employees should also know about qualified small business stock (QSBS). If you hold eligible shares for 5 years in a qualified C corp, you may exclude up to $15 million, or 10 times your basis if greater, of capital gains from federal tax. It is hard to qualify and takes a lot of early planning, so talk to a professional.

How NSOs are taxed

Non qualified stock options are simpler but less favorable from a tax standpoint. When you exercise, the spread between the strike price and market value is taxed as ordinary income and shows up on your W2. With 10,000 NSOs at a $10 strike and a $30 market value, that is $200,000 of income at exercise. There is no AMT issue, but tax is due immediately at exercise.

How ESPP discounts work

Employee stock purchase plans let you buy shares through payroll deductions, often at up to a 15% discount. Hold the shares 2 years from grant and 1 year from purchase and the discount can qualify for long term capital gains treatment. It is easy to accumulate too much company stock this way, so use an ESPP intentionally.

Managing concentration risk in company stock

When your salary, bonus, and investments all depend on one company, you have what I call double exposure risk, which is closely related to the concentrated stock trap. The diversification plans we build for clients have three steps:

1. Map liquidity. Know when shares vest, lock ups end, and windows open.
2. Model taxes. For some people, spreading exercises or sales across tax years smooths AMT or capital gains exposure.
3. Systematically reduce risk. Sell a set percentage of vested shares each quarter and reinvest in a diversified portfolio.

The right approach depends on your company stage, grant type, cash flow, tax bracket, and long term goals.

Common questions

Are RSUs taxed when they vest or when you sell?

RSUs are taxed as ordinary income when they vest, based on the value of the shares at that time.

What is the difference between ISOs and NSOs?

With NSOs, the spread at exercise is taxed as ordinary income right away. With ISOs, the spread is not taxed for regular income tax purposes at exercise, but it can trigger AMT.

What is an 83(b) election?

It is a filing made with the IRS within 30 days of an early exercise that asks to be taxed now.

VDB Wealth is a registered investment adviser. Information presented is for educational purposes only and is not intended to make an offer or solicitation for the sale or purchase of any specific securities, investments, or investment strategies. Investments involve risk and, unless otherwise stated, are not guaranteed. Past performance is not indicative of future performance.

If you work in tech or a high growth startup, there’s a good chance that a big chunk of your compensation isn’t your paycheck, it’s your equity.

And for many professionals, that’s where real wealth is built… or lost.

The challenge? Equity comp is filled with acronyms, RSU, ISO, NSO, AMT, 409A, 83(b), and each one can completely change your tax outcome.

So in this video, we’re going to walk through everything you need to know, clearly and calmly, from how equity comp actually works to how a wealth manager thinks about taxes, timing, and diversification.

This is a topic I help clients navigate at VDB Wealth, and today I’m going to share exactly how I approach it.

Let’s get started.

Understanding equity compensation

When companies talk about total compensation, they usually mean three parts:

Base salary. Bonus or commission. And equity, stock or options meant to align your incentives with the company’s success.

It’s a way to say: “We’re in this together, if we win, you win.” But there’s more than one way to give equity. The most common types are:

RSUs, Restricted Stock Units. Stock Options, either ISOs or NSOs. ESPPs, Employee Stock Purchase Plans.

Each one comes with its own timing, tax rules, and risk. So let’s start with the most common, RSUs.

RSUs, the public company standard

Restricted Stock Units, or RSUs, are the simplest form of equity, and the go to choice for most public companies like Microsoft, Amazon, Salesforce, and Meta. Why? Because they’re straightforward.

You don’t buy anything. You don’t choose when to exercise. Your company simply says: “We’ll grant you shares over time, as long as you stay here.”

That “over time” is called vesting. A common schedule is four years with a one year cliff, so 25% vests after your first year, and the rest monthly or quarterly after that.

How RSUs are taxed

When your RSUs vest, they become yours, and the value of those shares counts as ordinary income. The IRS is treating it as income for you that your company is just choosing to pay in stock.

Let’s say 1,000 shares vest at $50/share. That’s $50,000 of income added to your W2. Most companies automatically sell some shares to cover taxes, typically withholding 22% federal.

Here’s the problem: If your actual tax bracket is 32%, 35%, or 37%, that 22% won’t be enough.

So when you file taxes next spring, you might owe several thousand dollars in under withholding.

That’s why we often plan ahead for each vest, setting aside cash or selling a small portion to stay tax neutral.

What happens after vesting

After vesting, you fully own those shares. If the stock goes up, future gains are capital gains, short term if held less than a year, long term if held longer.

But here’s the catch: RSUs are taxed at vesting, not sale.

Example: If your RSUs vest when the price is $100, but the stock falls to $60 by year end, you’re still taxed on $100/share.

That’s called phantom income risk, paying tax on value that disappears.

So with RSUs, the key question is: “Do I want to hold more of the same company that already pays me?”

For many people, the smart move is to sell vested shares gradually and diversify.

RSUs: planning framework

When I build plans for clients, we walk through three key steps:

Understand the vesting schedule and blackout periods. Model taxes for each vesting event. Create a systematic sale plan, balancing diversification and tax efficiency.

That structure turns what feels random into a predictable wealth building process.

ISOs, incentive stock options (the startup standard)

ISOs are common at private tech companies and startups, especially before an IPO. They’re popular because they can lead to lower long term tax rates if managed carefully.

Here’s the simple flow:

You’re granted ISOs, no taxes yet. You exercise them, buy the shares at your strike price. You later sell those shares, hopefully for a gain.

To qualify for the best tax treatment (long term capital gains), you have to meet two holding period rules:

Hold the shares at least one year after you exercise, and two years after the original grant date.

If you check both boxes, your profit, the difference between the sale price and your strike price, is taxed as long term capital gains, not ordinary income.

That’s great news because long term capital gains rates are typically much lower, think 15 to 20% instead of 35 to 40%.

Example: how ISOs work in practice

Let’s make it real.

Say Sarah joins a startup and is granted 10,000 ISOs with a strike price of $1 per share. Three years later, the company’s fair market value is $10 per share.

If Sarah exercises now, she’ll pay $10,000 to buy her shares (10,000 × $1). On paper, she now owns stock worth $100,000 (10,000 × $10).

That $9 difference per share, called the bargain element, is not taxed right now for regular income tax purposes. But for the Alternative Minimum Tax (AMT) system, it counts as extra income.

The AMT trap, where ISO holders get caught

This is the part people miss.

When you exercise ISOs, the IRS looks at that bargain element, the gap between your strike price and the stock’s fair market value, and adds it to your AMT income.

If that pushes you over the AMT threshold, you might owe 26 to 28% tax even though you haven’t sold a single share.

Example: If Sarah exercises those 10,000 ISOs at $1 when the fair market value is $10, she has a $9 × 10,000 = $90,000 AMT adjustment. Depending on her other income, that could mean $20 to 25k of AMT owed… with no cash from selling shares.

That’s why so many startup employees get blindsided by big tax bills when they exercise options late in the game.

Early exercise & the 83(b) election, the smart move (if you can)

Here’s a strategy the pros use: early exercise.

Some companies let you buy your options before they vest. If you do that when the fair market value and strike price are basically the same, say, both $1, there’s no meaningful spread.

You then file an 83(b) election with the IRS within 30 days. That tells the IRS: “Tax me now, when this is worth almost nothing, not later when it’s worth a lot.”

If the company takes off, all future growth is treated as capital gains.

Example: Sarah early exercises 10,000 shares at $1 when the value is also $1. There’s no tax now. Five years later, the company IPOs at $50 per share, her $49 gain per share is long term capital gain.

If she hadn’t early exercised, she might have faced hundreds of thousands in AMT.

Of course, if the company fails, she’s out her exercise cost, maybe a few thousand dollars. So there’s still risk.

If you wait too long to exercise

Now imagine the opposite.

You wait until right before the IPO to exercise. Your strike is $2, but the fair market value is $50. On 20,000 shares, that’s $960,000 of AMT income.

You could owe over $200,000 in tax on shares you can’t even sell yet. That’s the worst case scenario, big tax bill, no liquidity.

So with ISOs, early planning is everything.

If you do end up paying AMT, it’s not always lost. You can earn something called an AMT credit, which you can use to offset taxes in future years when your regular tax is higher than your AMT.

In practice, that means if you owe $30,000 of AMT this year, you might recover some of that over the next few years once you start selling shares.

NSOs, non qualified stock options

NSOs are simpler but less favorable tax wise.

When you exercise NSOs, the spread between strike and market value is taxed as ordinary income, appearing on your W2. Any later appreciation becomes capital gains when you sell.

There’s no AMT issue, but taxes are due immediately at exercise.

Example: 10,000 NSOs at a $10 strike, market value $30: $200,000 of income today. If you sell later at $40, the extra $10/share is capital gain.

Most public or later stage companies favor NSOs because they’re easier to administer and predictable for accounting.

Private company valuations (409A)

For private firms, the 409A valuation sets the fair market value of the stock. It’s updated at least annually or after major events.

That valuation determines the minimum strike price for new grants, and it’s the number used for tax calculations when you exercise.

Knowing your 409A value is essential for early exercise decisions and AMT modeling.

QSBS, the holy grail for some

One last thing for early stage employees: Qualified Small Business Stock, or QSBS.

If you hold eligible shares for 5 years in a qualified C Corp, you may exclude up to $15 million (or 10x your basis, whichever is greater) of capital gains from federal taxes.

That’s enormous, and yes, it applies to many startups if structured right. Importantly, you need to exercise your options before the company reaches a certain scale.

While this sounds like an incredible structure, it’s harder to qualify and requires a lot of early planning so talk to a professional.

ESPPs, a quick win

Employee Stock Purchase Plans are usually the simplest way to gain ownership, and one of the few “free lunches” in finance.

You buy shares via payroll deductions, often at up to a 15% discount, sometimes with a “look back” that uses the lower of the start or end price of the purchase window.

That’s an immediate gain. Hold those shares for 2 years from grant and 1 year from purchase, and that discount can qualify for long term capital gains treatment.

Just remember: it’s easy to accumulate too much company stock this way, so use ESPPs intentionally, not automatically.

Managing risk, taxes, and diversification

Even when you understand the mechanics, the bigger question is strategy.

How do you manage risk when your salary, bonuses, and investments are all tied to the same company?

That’s what I call double exposure risk, when both your job and your net worth depend on one stock.

We build diversification plans for clients with three main steps:

Map liquidity. Know when shares vest, lock ups end, and windows open.

Model taxes. ISOs vs. NSOs vs. RSUs have very different impacts. For some, spreading exercises or sales across tax years smooths AMT or capital gains exposure.

Systematically de risk. Sell a set percentage of vested shares quarterly and reinvest into a diversified portfolio, U.S. stocks, international, bonds, real assets, or even fund future lifestyle goals.

Example: An Amazon engineer might sell 25% of each RSU vest to fund a down payment, build a portfolio, or max retirement accounts, instead of letting 80% of their wealth ride on AMZN.

These are the details that separate paper wealth from real wealth.

Equity compensation can be life changing, but it’s complex. There’s no one size fits all answer.

The right strategy depends on your company stage, grant type, cash flow, tax bracket, and long term goals.

But when you approach it intentionally, understanding how each decision fits together, you can turn confusing acronyms into an actual wealth building plan.

If you’re navigating RSUs, ISOs, or NSOs and want guidance on how to manage taxes, risk, and diversification, make sure you’re working with someone who truly understands this space.

At VDB Wealth, that’s exactly what we do, thoughtful, data driven planning for tech professionals and executives who want clarity and control.

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Thanks for watching, and remember, your equity should serve you, not the other way around.