Private Company Stock and Taxes: What Happens When You Owe Tax Before You Can Sell?

It's February and you open an email from your CPA. The number at the bottom (your tax bill, due April 15th) is six figures and is not what you were expecting. You have the shares to cover it; unfortunately, you can’t sell them.

That gap, between when the IRS wants its money and when private company stock becomes cash, is where most of the avoidable damage happens in private company equity planning. The tax obligations arrive on the IRS's schedule. The liquidity arrives on the company's.

This is especially relevant if you work at a late-stage private company, are thinking about exercising options, hold RSUs at a company staying private longer than expected, or participate in tender offers and buybacks. The mechanics differ across the 83(b) election, NSO and ISO exercises, and single-trigger RSU vesting. The pattern is the same: a tax bill before there's a way to pay it.

The 83(b) Election: Paying Tax Early in Exchange for Potential Future Tax Savings

An 83(b) election most commonly comes up with restricted stock, sometimes called a restricted stock award or RSA. This is different from a restricted stock unit, or RSU.

With restricted stock, actual shares are transferred to you up front, but those shares are subject to vesting. If you leave before they vest, the company may have the right to repurchase the unvested shares. Because actual stock has been transferred, the default tax treatment is that you are taxed as the restrictions lapse, usually as the shares vest, based on the fair market value at that time.

An 83(b) election lets you choose a different treatment. Instead of waiting to be taxed as shares vest, you elect to include the value of the restricted stock in income now, based on the value at the time the shares are transferred. For early employees at a company with a very low 409A valuation, this can create meaningful tax savings. You may pay a relatively small ordinary income tax bill up front, and if the stock later appreciates and is eventually sold at a gain, future appreciation may be taxed at long-term capital gains rates if the holding-period requirements are met.

That is very different from a typical RSU. With an RSU, you generally do not own actual shares at grant. Instead, you have a promise that shares or cash will be delivered later if vesting and settlement conditions are met. Because no actual property has usually been transferred at grant, an 83(b) election generally is not available for RSUs.

The 83(b) is a bet you cannot unwind. If you file and pay taxes up front, and the company fails or the stock never appreciates, you have paid tax on value that never turned into money. There is also a strict 30-day filing window from the date the property is transferred. Miss it, and the opportunity is gone.

Before filing, ask: How much cash would the tax bill require today? What would you lose if the company failed? How likely are you to stay through vesting? And how meaningful is the upside relative to your broader financial life?

Private Company Stock Options: NSO Taxes, ISO AMT, and Liquidity Risk

Stock options give you the right to buy shares in your company at a fixed price, called the strike price, before the options expire. The two main types, nonqualified stock options and incentive stock options, have meaningfully different tax treatment. Both can create situations where you owe taxes before you are able to generate cash from the shares.

When you exercise a nonqualified stock option, or NSO, the spread between your strike price and the current fair market value is taxed as ordinary income in the year you exercise. For a private company, fair market value is typically based on the company's 409A valuation. This income usually runs through payroll and appears on your W-2, which means it is also subject to withholding and employment taxes.

Supplemental wage withholding is often done at a flat 22% federal rate, unless higher mandatory withholding applies for very large amounts. If you are in the 35% or 37% federal tax bracket, that 22% withholding may leave a meaningful gap. On an exercise where the taxable spread is $300,000, that federal withholding gap could translate to roughly $39,000 to $45,000 owed later, on top of whatever was already withheld. State taxes may create an additional gap.

At a public company, you may be able to sell shares to cover the shortfall. At a private company, you typically cannot. You are paying for the shares, the tax, and the investment risk from existing cash.

ISOs can receive more favorable tax treatment in the right circumstances. If you exercise ISOs and meet the required holding periods, generally at least two years from the grant date and one year from the exercise date, the gain may qualify for long-term capital gains treatment when you sell, rather than being taxed as ordinary income.

The complication is the alternative minimum tax, or AMT. When you exercise ISOs and hold the shares rather than selling them in the same year, the spread between your strike price and the 409A valuation is generally treated as an AMT preference item. That means the spread can count as income for AMT purposes even though you have not sold the shares, have not received cash, and may have no realistic way to turn those shares into cash.

This does not mean exercising ISOs is a bad strategy. Holding for preferential tax treatment can be the right call. Exercising ISOs at a private company should include careful AMT modeling before you pull the trigger.

Before exercising options, ask: What is the taxable spread today? What tax will be withheld automatically, and what might still be due later? Can you cover both the exercise cost and the tax cost without relying on a future liquidity event? How much of your net worth will be tied to one private company after exercise?

Single-Trigger RSUs at Private Companies: Taxable Vesting Without Liquidity

Most private company RSUs are structured with double-trigger vesting. The shares vest on a time-based schedule, which is the first trigger, but you do not actually receive shares and owe income tax until a liquidity event, such as an IPO or acquisition, also occurs. That liquidity event is the second trigger.

This structure is common because it helps solve the liquidity problem. The tax bill and the ability to sell usually arrive around the same time.

Some large, established private companies use single-trigger vesting instead. Shares vest based on time alone, without requiring a liquidity event. When your shares vest, you may own them, and the value may be taxable as ordinary income based on the company's valuation at that time, even if there is no public market for you to sell.

This creates a current tax obligation on stock that may not have a liquid market. If you are at a company with a high valuation and a significant vest in a given year, the tax bill can be substantial.

You may have a few ways to handle it. Some companies allow employees to request higher supplemental withholding before a vest date, but you usually need to ask HR, payroll, or your equity plan administrator before the vest occurs. You may be able to pay the tax bill from existing cash if you have been setting money aside. If your company runs periodic tender offers or buybacks, you may be able to sell a portion of your shares to generate liquidity.

The constraint is timing. Tender offers happen when the company decides to run them, not necessarily when your tax obligations are due. Estimated tax payment deadlines and tender offer windows may not line up. There may also be limits on how much you are allowed to sell, and those limits may not be sized to your tax obligation.

This is why we encourage clients to map out their vesting schedule against the historical cadence of their company's tender offer program early in the year. If there is a mismatch, knowing early gives you time to build cash reserves. Discovering it late gives you fewer options.

What This Year Looks Like Without a Plan

Take the situation in the opening. A six-figure bill from the CPA, shares that cannot be sold to cover it, eight weeks until April 15th. Here is what the year typically looks like from there, without an integrated plan.

The brokerage account that was supposed to become a down payment gets liquidated. The rest of the bill comes from a loan from parents, with a promise to pay it back inside a year, which means mom now asks how work is going with a very specific kind of follow-up energy.

A few months later, the company announces a tender offer. The window is short, often two weeks. There is usually a cap on how much can be sold, and the price is set by the company. Shares get sold, parents get repaid, the brokerage account starts rebuilding. Two large taxable transactions have now happened in one year, neither modeled against the rest of the year's income, prior option exercises, or the likely tax bracket on the year-end bonus.

When April comes around again, the bill is bigger than expected. Again.

The remaining equity keeps vesting. The 409A keeps climbing. The cycle continues.

What This Year Could Look Like Instead

Same person, same company, same equity. Different planning.

The work starts in January, not February. The vesting schedule gets pulled against the historical cadence of the company's tender offers, and any gap between tax events and selling windows becomes visible months ahead of the bill. The income picture for the year, including the bonus, any planned option exercises, and the expected vests, gets modeled as one integrated tax projection. Where withholding is going to fall short, a higher rate gets requested from payroll before the income event, not after.

When the next tender offer opens, the decision about how much to sell, why, and what to do with the proceeds has already been made. What is happening in the tender window is the execution of a plan made months earlier.

The brokerage account keeps growing. The down payment stays on the calendar. The holidays go back to being about whether the turkey is going to be done on time.

Most of These Decisions Are Easier to Make Before You Need To

The common thread is that advance planning makes every one of these situations more manageable.

An 83(b) election has a 30-day window that does not reopen. AMT exposure from an ISO exercise is much easier to model before you exercise than to pay after. A tax shortfall from single-trigger RSUs is much easier to prepare for when you know it is coming than to scramble for after the fact. Tender offers are easier to use strategically when you already know how much liquidity you want and why.

Private company equity rewards employees who take the time to understand what they are holding. The tax obligations, vesting mechanics, and liquidity constraints can all be mapped in advance, with the right team in place.

If you are holding private company equity and trying to decide whether to exercise options, file an 83(b) election, prepare for RSU taxes, or sell in a tender offer, these decisions are worth modeling before the deadline arrives. The cost of getting them wrong is rarely just the tax bill. It is the down payment that got cashed in, the loan from a parent that changed the tone of every phone call for a year, and the next April that arrives with the same problem, slightly larger.

Frequently Asked Questions

Do I owe taxes when my private company RSUs vest?

It depends on how your RSUs are structured. If your company uses double-trigger vesting, you generally do not owe income tax until a liquidity event like an IPO or acquisition also occurs and the shares settle. If your company uses single-trigger vesting, you may owe ordinary income tax at each vest date based on the fair market value of the shares, even if there is no public market for you to sell them.

What is single-trigger vesting and how is it different from double-trigger vesting?

Double-trigger vesting means shares vest on a time schedule and require a second event, such as an IPO or acquisition, before shares are delivered and income tax is triggered. Single-trigger vesting means shares vest based on the time schedule alone. With single-trigger vesting, employees may owe tax before they have access to public-market liquidity.

What happens if I cannot cover my tax bill from a private company vest?

Your options may include paying from existing cash, increasing withholding before the vest if your company allows it, selling shares through a company-sponsored tender offer or buyback if one is available, or making estimated tax payments from other resources. If none of those options produces enough cash, you may be underpaid and could owe penalties or interest. The best protection is mapping out expected tax obligations before vest dates and building liquidity reserves accordingly.

What is the AMT trap for ISO holders at private companies?

When you exercise incentive stock options and hold the shares rather than selling them in the same year, the spread between your strike price and the company's fair market value may count as income for alternative minimum tax purposes. That can create a tax bill on value that exists only on paper. At a private company, where you may not be able to sell shares to cover the tax, the bill has to come from other cash resources. AMT paid may sometimes be recovered as a credit in future years, but the timing mismatch can still create a real cash problem.

What is an 83(b) election, and when does it make sense?

An 83(b) election applies when actual property, such as restricted stock, has been transferred to you and is subject to vesting or other restrictions. It allows you to include the value in income at the time of transfer rather than waiting to be taxed as the shares vest. It tends to make the most sense when the current value is low, the upfront tax cost is manageable, and the potential future appreciation is meaningful. The election must generally be filed within 30 days of the date the property is transferred.

Can I make an 83(b) election on RSUs?

Generally, no. A typical RSU is not actual stock at grant. It is a promise to deliver shares or cash later if vesting and settlement conditions are met. Because actual property has not usually been transferred at grant, an 83(b) election is generally not available for RSUs.

What is a tender offer, and can I use it to pay taxes on my equity?

A tender offer is a company-sponsored liquidity program where the company or an outside investor purchases shares from employees at a set price. It can be one way to generate cash from private company equity before an IPO or acquisition. The limitation is timing. Tender offers happen on the company's schedule, and tax deadlines may arrive before you are able to sell. Tender offers may also limit how much you can sell, which may or may not be enough to cover your full tax obligation.

Why might standard supplemental withholding not cover my taxes?

Supplemental wage withholding is often done at a flat federal rate that may be lower than your actual marginal tax rate. If you are in a higher federal bracket, and especially if you also owe state tax, the amount withheld may not be enough. That can leave you with a balance due when you file your tax return or when estimated tax payments are required. Some companies allow employees to request higher withholding, but you usually need to ask before the income event occurs.

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Stephanie Bucko and Cristina Livadary are fee-only financial planners based in Los Angeles, California. Stephanie is the Chief Investment Officer and Cristina is the Chief Executive Officer at Mana Financial Life Design (FLD). Mana FLD provides comprehensive financial planning and investment management services to help clients grow and protect their wealth throughout life’s journey. Mana FLD specializes in advising ambitious professionals who seek financial knowledge and want to implement creative budgeting, savings, proactive planning and powerful investment strategies. As fee-only fiduciaries and independent financial advisors, Stephanie and Cristina never receive commission of any kind. Stephanie and Cristina are legally bound by their certifications to provide unbiased and trustworthy financial advice.