Why Your Micron RSUs Cost More in Taxes Than You Expected

By JT Belnap | Treasure Valley Financial Planning | 2026 | 8-minute read

 

I want to tell you about a conversation I have a few times a year.

Someone calls us in February or March. They have just sat down with their tax return, and the number on the screen does not match the number in their head. They are not in trouble. They are not being audited. They just owe more than they expected, and nobody warned them it was coming.

More often than not, it came from their RSUs.

And here’s the thing. It’s not because RSU taxation is complicated. It’s pretty straightforward once you see how it works. The problem arises when Micron doesn’t withhold taxes on RSU vests at the rate an employee owes. And the difference sits quietly until April, when it shows up as an unplanned bill.

If you are a Micron Technology employee in the Treasure Valley, this guide is for you. We are going to walk through exactly how your RSUs are taxed, where the withholding gap comes from, and what you can do about it before it becomes your problem.

Three dates. Three completely different tax events.

Most of the confusion around RSU taxes comes from blending three things that need to stay separate.

The grant date is when Micron awards you the RSUs. Nothing happens from a tax standpoint. You do not own shares. You have a promise. Per IRS Publication 525, restricted stock units are not included in income at grant because you have not received property yet.

The vesting date is when that promise becomes actual shares, usually through settlement and delivery of stock. This is the moment when taxes are generally triggered, whether you sell the shares that day or hold them for years. Under IRC Section 83(a), the fair market value of whatever you receive becomes ordinary income when you receive it. If that weren’t enough, RSUs are also subject to Social Security and Medicare taxes.

The sale date is whenever you eventually sell those vested shares. At that point, any movement in price above your vest-day value becomes a capital gain or loss. But the original vest value has already been taxed as income. You will not pay twice on the same dollars.

Keep those three events separate in your mind. Everything else flows from that.

What actually happens when your RSUs vest

When your RSUs vest and shares are delivered, Micron reports the full market value of those shares on your W-2 right next to your salary. The IRS generally treats it like wage compensation. It is taxed at your marginal federal income tax rate, plus Idaho income tax, plus Medicare.

To cover the federal piece, Micron withholds using the standard supplemental wage flat rate of 22%, the same rate most large employers use for bonuses and RSUs. That rate is described in IRS Publication 15. The tax code allows this flat-rate method or an aggregate method that blends your RSUs into your regular paycheck withholding. Most large employers, including Micron, use the flat rate because it is simpler to administer. One note for the highest earners: the 22% flat rate applies only to the first $1 million of supplemental wages in a year. Any supplemental wages above $1 million are withheld at 37%.

Here is where the problem starts. For many Micron engineers and managers in the Treasure Valley, 22% may be below their actual marginal bracket.

For the 2026 tax year, RSU dollars stack on top of your regular salary. These are the confirmed 2026 married-filing-jointly brackets per IRS Rev. Proc. 2025-32:

Taxable Income (Married Filing Jointly)	Federal Rate
$0 to $24,800	10%
$24,801 to $100,800	12%
$100,801 to $211,400	22%
$211,401 to $403,550	24%
$403,551 to $512,450	32%
$512,451 to $768,700	35%
Over $768,700	37%

Let me put some numbers to it. Say you are a senior engineer with a base salary of $195,000. In March, $140,000 worth of RSUs vest. Your total W-2 income that year is now $335,000 before deductions and other adjustments. Micron withholds 22% on the vest, which is $30,800. But the federal brackets are based on taxable income, not gross W-2 income. After deductions, pre-tax contributions, spouse income, other income, and other adjustments are considered, a meaningful portion of those RSU dollars may still be taxed at 24% federally, not 22%, because the 24% bracket for joint filers runs from $211,401 up to $403,550 of taxable income.

On a $140,000 vest, the federal withholding gap can run into the low thousands in a 24% marginal bracket, and it can become much larger when spouse income, multiple vest events, bonuses, or other income push the household into the 32% bracket or higher. Idaho income tax adds another layer. And nobody sent a reminder. It just waits.

The numbers here are simplified for illustration. Your actual liability depends on your full taxable income, deductions, filing status, spouse income, and other income. But the direction is clear. The gap between what gets withheld and what you actually owe can be real and significant for many senior Micron employees.

That is the most common issue we see when Micron employees first come to us. And it is one of the most preventable, if you catch it before the vest rather than after the return.

If your base salary puts you near $200,000 and your RSUs push total income near $340,000, the marginal rate on a large portion of those RSU dollars may be 24%, not 22%, depending on taxable income. If taxable income climbs past $403,550, those dollars start being taxed at 32%, and the 35% rate does not begin until taxable income crosses $512,450. Micron does not know your complete household income picture. It withholds at the default rate. The gap is yours to manage.

Idaho’s 5.3% on top

Idaho taxes RSU vest income as ordinary income. For most Micron employees receiving RSU income, the incremental Idaho tax rate will be 5.3%, the top rate in effect for tax years beginning on or after January 1, 2025, per the Idaho State Tax Commission. There is no lower rate for equity compensation. It is treated the same as your paycheck.

On a $140,000 vest, a 5.3% Idaho tax rate equals $7,420 in state tax. Micron may withhold Idaho tax at vesting, but employees should verify the actual state withholding on the vest statement or paystub. Whether the amount actually covers your full-year liability, given everything else going on in your income picture, is a separate question your CPA should be looking at every year.

Social Security and Medicare

RSU vest income is also subject to payroll taxes. Social Security at 6.2% applies up to the 2026 wage base of $184,500, as announced by the Social Security Administration. If your Micron wages before the RSU vest already clear that number, the RSU vest generally will not add more Social Security exposure. Medicare at 1.45% has no cap. The 0.9% Additional Medicare Tax may also apply. For a married couple filing jointly, the tax applies to combined wages above $250,000. Employer withholding works differently: an employer generally begins withholding the 0.9% tax once that employee’s wages from that employer exceed $200,000, regardless of filing status. That can create over- or under-withholding depending on spouse income and total household wages.

Many senior Micron employees in the Treasure Valley cross the $250,000 household threshold. It is worth knowing whether it applies to you.

What happens when you sell

Once shares vest, you own stock. What you paid for it, in the eyes of the IRS, is the vest-day market value, the same number already on your W-2 as ordinary income. That is your cost basis. It is your starting point for any future gain calculation, and you do not pay tax on it again.

Sell immediately after vesting. Your gain is close to zero, since the price has not had time to move meaningfully. This is the cleanest outcome from a tax standpoint. A lot of Micron employees do this by default, and for good reason.

Hold less than a year, then sell. Any gain above your vest-day price is a short-term capital gain, taxed at ordinary income rates. At many Micron senior compensation levels, that can mean 24% to 32% federally, plus Idaho’s 5.3%. That can be a less attractive tax result than long-term treatment, though tax treatment should not be the only factor.

Hold more than a year, then sell. Gains qualify as long-term capital gains, taxed at preferential federal rates of 0%, 15%, or 20% depending on your taxable income. Which rate applies matters a great deal here. For 2026, joint filers stay in the 15% long-term rate across a wide band of taxable income, and the 20% rate does not begin until taxable income exceeds $613,700. So many Treasure Valley Micron households may land in the 15% bracket, not the 20% one.

For a household in the 15% long-term band with MAGI over $250,000, the combined rate works out to roughly 15% federal plus 3.8% Net Investment Income Tax plus 5.3% Idaho, or about 24.1% total. For a household high enough to reach the 20% federal rate, that same math comes to about 29.1% total. Knowing which side of that line you fall on is part of the planning conversation.

A quick note on that 3.8%. The Net Investment Income Tax is a federal surcharge on investment income that kicks in above $250,000 in modified adjusted gross income for married filers. That threshold has not moved for inflation since 2013. So every year, more Micron employees get pulled into it without realizing it.

Holding shares longer than a year can make sense for some people. It does not make sense for everyone. The tax savings from long-term treatment do not help much if the stock drops 30% while you are waiting for the calendar. And if you are already sitting on significant MU exposure through your ESPP, vested RSUs, taxable accounts, or any self-directed brokerage-window holdings inside your 401(k), holding more RSU shares might be adding to a concentration problem that deserves its own conversation.

Three ways to fix the withholding gap before April

If you know a vest is coming and you know your actual bracket is higher than 22%, you have options. Real ones.

Adjust your W-4 withholding. Ask Micron’s payroll team to withhold an additional flat dollar amount from each paycheck. Figure out your expected shortfall from last year’s vest, divide it across your remaining pay periods, and make up most of the gap before year-end. Simple to do. Most people just do not think about doing it.

Pay quarterly estimated taxes. The IRS estimated-tax rules are more nuanced than a simple dollar threshold. In general, estimated payments may be needed if you expect to owe at least $1,000 after withholding and refundable credits, and your withholding and credits will be less than the smaller of 90% of your current-year tax or 100% of your prior-year tax, or 110% for certain higher-income taxpayers. The 2026 federal estimated tax deadlines are April 15, June 15, September 15, and January 15, 2027. Idaho has its own schedule that generally runs parallel. Your CPA should be calculating this after each vest event, not in March when the damage is already done.

Set aside the difference right away. Right after a vest, if you know the withholding came up short, move the difference into a dedicated savings account immediately. Do not let it blend into your checking and disappear into everyday spending. It is not a glamorous solution, but it works.

But here is the bigger opportunity most people miss. Those three steps manage the bill. They do not reduce it.

The earlier we get in front of your situation, the more options we have. A conversation in August or September, before the year closes, still leaves time to deploy strategies that can meaningfully lower your actual tax exposure. Charitable giving decisions, retirement account contributions, timing of stock sales. Things that only work if they are in place before December 31.

Waiting until February to call a tax preparer means most of those doors are already closed.

That is exactly why we created the Treasure Valley Family Office. So our CPAs and advisors can work on this together, throughout the year, not just at filing time. After a vest event, we calculate exactly what was withheld, what you actually owe, and what opportunities still exist before year end. That is the practical difference between having a coordinated team in your corner and scrambling in the spring.

And when the plan is in place, when you are not dreading April, not wondering if you missed something, not leaving money on the table, that clarity compounds. It frees you to actually enjoy what you have built. To be present with your family. To give generously. To make decisions from a place of confidence instead of anxiety. That is what getting this right is really about.

How this connects to everything else

RSUs do not exist in isolation. In the same year you are dealing with a vest event, you might also be selling ESPP shares, making 401(k) contributions, and generating investment income elsewhere. Every one of those affects your bracket, your NIIT exposure, and your Idaho liability at the same time.

Handled well, they work together. Handled without a coordinated view, they can push you into a bracket you did not see coming, or turn a smart move in one account into a costly mistake in another.

That is even more true for Micron employees who are within five years of retirement. If you are thinking about reducing a concentrated MU stock position, the timing of your RSU sales is part of that analysis. If a Roth conversion is on the horizon, the year you have a large vest may or may not be the right window, depending on your full income picture.

Many Micron employees we talk to have been managing their equity compensation, their taxes, and their retirement accounts with three different professionals who do not talk to each other. The strategies available to them, particularly in the two to three years before retirement, are more powerful when they are coordinated. In some cases, better coordination can produce five-figure tax savings over time, but the larger point is avoiding avoidable surprises and making each decision fit the broader plan. It is what those dollars go on to do, for your retirement, your family, and the things you have actually been working toward.

Questions we hear about Micron RSUs

The short version

The 22% withholding gap can be real. Idaho’s 5.3% top rate adds to it. And for Micron employees with significant RSU income, the gap between what gets withheld and what you actually owe can be substantial.

None of this is hard to manage. It just needs to be managed intentionally, before the vest event, not after the tax return.

If you are within five years of retirement and want to know exactly where you stand, that is the conversation we have every day.

Request a private consult. No pressure. Just an honest look at your situation.

 

Treasure Valley Financial Planning is a fiduciary financial planning firm based in Meridian, Idaho, serving Micron Technology employees and tech professionals across the Treasure Valley and nationwide. This article is for educational purposes only and does not constitute tax, legal, or investment advice. Consult a qualified tax professional and estate planning attorney for guidance specific to your situation.

Sources: IRS Publication 525; IRS Publication 15; IRS Publication 15-T; IRC Section 83(a); IRS Revenue Procedure 2025-32; IRS Net Investment Income Tax guidance; Idaho State Tax Commission; Social Security Administration 2026 Wage Base; IRS Publication 5992, Equity (Stock)-Based Compensation Audit Technique Guide.