You Can't Change the 22% RSU Withholding. Here's What You Can Do Instead.

You're a VP of Engineering at a large public tech company. Seven years in. Your RSUs vest quarterly at about $150,000 a quarter. Your company withholds 22% for federal taxes, same as it always has. The shares hit your brokerage account, you pay your bills, and you move on. And then April comes, and you write a check for the difference. $20,000. Maybe $30,000. Maybe more.

The surprise isn't your fault. The system is designed to under-withhold. But here's what almost nobody tells you: you can fix it before it happens. You just need to know which levers actually exist and which ones don't.

Why 22% Is the Rule (Not a Choice)

The IRS classifies RSUs as supplemental wages. When your company vests shares, it can choose one of two withholding methods. Most large public companies pick the flat-rate method: 22% of the value at vesting, full stop. The alternative, the aggregate method, applies your marginal rate but requires the payroll system to calculate withholding on the combined total of your salary and the RSU value in the same pay period. Most companies don't run their payroll that way.

So 22% it is. And 22% is almost certainly less than your actual marginal rate.

The Gap in Real Terms

Here's how the mechanics work in a representative situation. A senior director with $150,000 in quarterly RSU vests, a $350,000 salary, and total annual income pushing past $600,000 is in the 35% federal bracket. Her company withholds 22% on the RSU. That leaves roughly $19,500 per quarter in federal tax not covered by withholding.

Multiply that across four quarters, and the gap adds up fast.

Before California's 12.3% or the 3.8% net investment income tax if her modified AGI crosses the threshold. April becomes a blindside, every year.

Fix One: Adjust Your W-4 to Pull More From Salary

You can't change the 22% rate on the RSU itself. But you can change what gets withheld from your regular salary. The W-4 has a line for additional withholding. If you know your RSUs will vest at $150,000 a quarter and you want to cover the gap, you can ask payroll to withhold, say, an extra $4,000 per biweekly paycheck. Your salary withholding uses your actual marginal rate, so the extra dollars flow to the IRS throughout the year, not in one lump sum in April.

The catch: your company's payroll system still applies 22% to the RSUs regardless of what your W-4 says. The W-4 adjusts your regular wage withholding only. That's why you need to do the math yourself, or work with someone who will walk through it with you.

Fix Two: Quarterly Estimated Tax Payments

If adjusting salary withholding doesn't feel right, or if your compensation is mostly RSUs with a small base salary, quarterly estimated tax payments are the direct route.

The IRS requires estimated payments when you expect to owe at least $1,000 after subtracting withholding and credits. For a tech executive with significant RSU income, the standard approach is to calculate the expected shortfall for the year, divide by four, and send payments by April 15, June 15, September 15, and January 15 of the next year. Each payment covers the gap from the preceding quarter's vesting.

The key detail: estimated tax payments are tied to income timing. If your RSUs vest in March but you don't make an estimated payment until June, you may owe a small penalty for the late payment. The safe harbor rule protects you if you pay at least 100% of last year's tax liability (110% if your adjusted gross income was over $150,000) through withholding and estimated payments combined.

The Real Fix: A Year-Round Strategy

Both fixes above are tactics. They work. But they treat each year in isolation. The real fix is a year-round strategy that plans the withholding before the RSUs ever vest.

A tax strategist who works with equity comp looks at the full picture in January, or even the November before. They map out each vesting date, each expected grant, the salary and bonus, the investment income, the state tax picture, and the 3.8% NIIT threshold. Then they build a withholding and estimated payment plan that covers all of it, quarter by quarter, so cash flow stays predictable and April stops being a surprise.

That's the difference between a preparer who files what happened and a strategist who designs the outcome before the year closes. A preparer sees the 22% withholding and files the return. A strategist sees the 22% withholding, knows it's not enough, and tells you what to do about it in Q1.

If you're a senior tech executive in San Diego, Frisco, or anywhere in between and you'd like a second look at your RSU withholding picture before Q3 ends, book a free 15-minute discovery call at (619) 280-2700 or email info@RoadmapTax.com. The paid strategy session is where the real deliverable lives, but the free call is where we figure out if it's the right fit.

FAQ

Why does my company only withhold 22% on RSUs?

The IRS classifies RSUs as supplemental wages. Most employers use the flat-rate withholding method, which caps federal withholding at 22% regardless of your tax bracket. Your company could use the aggregate method to withhold at your marginal rate, but most large public companies choose the flat-rate method for payroll simplicity.

Can I ask my employer to withhold more than 22% on my RSUs?

Not directly through the RSU withholding itself, no. But you can adjust your W-4 to request additional withholding from your regular salary, or make quarterly estimated tax payments to cover the gap.

What happens if I don't cover the withholding gap?

You will owe the difference when you file your tax return in April. If the shortfall is large enough, you may also owe an underpayment penalty. The IRS expects taxes to be paid throughout the year, not in one lump sum at filing time.

How do quarterly estimated tax payments work for RSU income?

You calculate the expected tax shortfall from your RSU vests, divide by four, and send payments by April 15, June 15, September 15, and January 15. The payments are tied to the quarter in which the income was received.

What is the safe harbor for estimated taxes?

You will not owe a penalty if your withholding and estimated payments total at least 100% of your prior year's tax liability (110% if your adjusted gross income was over $150,000). This is especially useful when your RSU income fluctuates year to year.

Is this something a CPA would handle as part of filing my return?

A traditional preparer files what happened. A tax strategist plans what should happen before the year ends. Most CPAs who focus on compliance will not proactively set up a mid-year withholding plan unless you ask. That is the difference between filing and strategy.