Your RSUs are vesting, or you're about to exercise some nonqualified stock options, and your equity portal throws a question at you: do you want federal withholding at 22% or 37%?

It looks like a simple toggle. Pick 22% and hang onto more stock. Pick 37% and play it safe. But is 37% actually the safe choice? And what happens if 22% turns out to be nowhere near enough?

This option is still relatively new and only offered at a handful of companies — most employees don't get a say in their withholding rate at all. But if your company gives you the choice, that single click can meaningfully affect how much stock you end up holding and whether you're writing a check at tax time. Pick wrong in either direction, and you either face a surprise tax bill or hand over more shares than you needed to.

Why Does Any of This Get Withheld in the First Place?

When RSUs vest, the value of those shares generally counts as compensation and gets added to your taxable wages — even though you received stock, not cash. Vest 1,000 shares at $50 each, and you've just picked up $50,000 of additional W-2 income. Your employer still has to withhold federal and state tax (plus applicable payroll tax) on that amount, even though no cash landed in your checking account.

NSOs work similarly: the spread between your exercise price and the stock's fair market value at exercise is treated as compensation and shows up on your W-2.

Since you're not getting a cash bonus to cover this, companies typically handle it through a sell-to-cover or withhold-to-cover transaction — selling or withholding a portion of the newly vested or exercised shares to cover the tax bill, and releasing the rest to you. With NSOs, you may also need to fund the exercise price itself.

Why 22% Shows Up So Often

RSU and NSO income generally runs through payroll as supplemental wages. Under the IRS's flat-rate method, employers can withhold federal income tax at a flat 22% on supplemental wages, as long as your total supplemental wages for the year stay under $1 million. Cross that $1 million mark, and the amount above it is subject to mandatory 37% withholding.

Historically, most employees never got a choice — the company just applied 22% (or 37%, once the mandatory threshold kicked in) automatically. Now, some companies are letting employees elect a higher withholding rate voluntarily. If your plan only offers 22% or 37%, you're stuck picking between those two — you generally can't type in 30% just because it feels closer to your actual rate.

And here's the thing worth internalizing: neither 22% nor 37% is necessarily your real tax rate. Both are just prepayments toward whatever your actual tax bill turns out to be once your full return is calculated — salary, bonus, spouse's income, investments, other equity events, deductions, and credits all factor in. Your equity portal knows how many shares are vesting. It has no idea what your total tax picture looks like.

Why 22% Is Often Not Enough

If you're receiving substantial RSUs or exercising valuable NSOs, there's a real chance your marginal tax bracket is already well above 22% — especially once you stack a high base salary, a working spouse, investment income, and a large equity event all into the same year.

Say an additional $100,000 of RSU income lands you in the 32% bracket. Withholding at 22% collects $22,000 — but the actual federal tax on that income is closer to $32,000. That's a $10,000 gap that doesn't disappear just because your employer called it "22% withholding." You'll need to close it — through a higher equity withholding election, extra withholding on your regular paycheck, an estimated tax payment, or some combination — and it's far better to find that gap while you still have time to plan around it than to discover it when your return is being prepared.

But Isn't 37% the Safe Choice?

Not automatically. Choosing 37% does reduce your risk of being underwithheld, but it can also mean giving up considerably more stock than you actually needed to.

On that same $100,000 of compensation: 22% withholding is $22,000; 37% withholding is $37,000 — a $15,000 difference. If shares are being sold to cover that tax, choosing 37% means parting with roughly $15,000 more in stock value than the 22% election would have required.

Will you get the overpayment back? Generally, yes, once your return is filed. But you get back dollars, not shares. If the stock appreciates while you're waiting to file, you don't participate in that growth on the shares that were already sold or withheld — the government refunds the excess tax, not the investment position you gave up. (Of course, if the stock drops instead, selling more at vesting might have actually reduced your risk — which is exactly why this isn't purely a tax question. It's a cash-flow and investment decision too.)

Two Real Scenarios Worth Learning From

Case one: An employee whose plan allowed paying the withholding in cash instead of surrendering shares wanted to keep as much stock as possible. Before committing to that, a real look at projected household income, other withholding already in place, upcoming equity events, and available cash was worth doing — along with an honest conversation about how concentrated their net worth already was in a single company's stock. After running the numbers, paying cash and keeping more shares turned out to be the right call — because it genuinely matched their goals and didn't strain their emergency fund.

Case two: Another employee, facing a portal deadline with only "22% or 37%" on the table, picked 37% because it simply sounded more responsible. When the full-year tax projection came together later, it turned out they'd significantly overwithheld — more stock surrendered than the actual tax bill required. They'd get a refund eventually, but the shares themselves were already gone. Nothing reckless happened here — just a cautious decision made without enough information, built on the assumption that the higher number is automatically the safer one.

Neither case had an obviously "correct" universal answer. What made the difference was running the actual numbers before clicking anything.

If Your Plan Lets You Pay Cash Instead

Some equity plans let you fund the withholding with cash rather than surrendering shares; others require a straight sell-to-cover with no alternative. If cash is an option, it's worth asking yourself a few honest questions before choosing it:

• Can you actually afford it? Would covering the tax bill in cash drain your emergency fund or crowd out another financial priority? Being "stock rich, cash poor" just to say you kept every share isn't automatically a win.

• How concentrated are you already? Your paycheck, benefits, and career may already be tied to this one company. Paying cash to keep more shares only deepens that concentration — do you have other investments balancing it out, or are most of your eggs already in this one basket?

• What else could that cash be doing? Paying down high-interest debt, building a diversified portfolio, funding a different goal entirely — every dollar spent keeping shares is a dollar not doing something else.

• Would you buy this stock today, with this same cash, if you didn't already own it? Not because you earned it, not because selling feels disloyal, not because you're hoping the price climbs. If the honest answer is no, that's worth sitting with before you use cash purely to preserve share count.

Remember: 22% and 37% Usually Only Cover Federal Income Tax

The election typically only addresses federal withholding. Your vest or exercise may also trigger Social Security and Medicare tax, state income tax, and potentially local tax — on top of whatever you owe toward the exercise price itself for NSOs. Choosing 37% doesn't mean only 37% of the total value is at stake; the real total, once everything else is layered in, is usually higher. Read your plan's election screen carefully, and if it's not clear which taxes are actually covered, ask before the deadline.

How to Actually Make This Decision

Rather than guessing between two buttons, work through the full picture:

1. What's your expected full-year income — salary, bonus, RSU vests, NSO exercises, spouse's income, everything?

2. What deductions and credits apply to you?

3. How much federal and state tax is already withheld year-to-date?

4. Are more vests, exercises, or bonus payments coming before year-end?

5. Have you made any estimated tax payments already?

6. Are you on track to meet the federal and state safe-harbor thresholds?

7. How many shares would actually be sold or withheld under each option?

8. Does your plan allow paying with cash instead of surrendering shares?

9. How much of this company's stock do you genuinely want to keep?

10. What does each choice do to your available cash and other financial priorities?

Once you've got real answers to these, the decision usually becomes much clearer — maybe 22% plus an estimated payment to cover the gap, maybe higher withholding from your regular paycheck instead, maybe 37% really is appropriate given your situation, or maybe you intentionally sell more shares because you're already overexposed to a single stock. There's no universally safe button — just an informed decision versus an uninformed one.

Don't Forget the Second Tax Trap: Cost Basis

The withholding election isn't the only place money quietly slips away with equity compensation. When RSUs vest, the amount included in your W-2 generally becomes your cost basis in those shares. For NSOs, basis generally includes the exercise price you paid plus the spread already taxed as compensation.

When you eventually sell, your brokerage's reported basis can be wrong or missing entirely — and if that's not corrected on your return, you risk paying tax twice on the same income. RSUs and NSOs both create two separate taxable events: ordinary income when the shares vest or options are exercised, and a separate capital gain or loss when you later sell. Don't assume your brokerage statement got the second part right — verify it, or have someone who specializes in equity compensation verify it for you.

The Bottom Line

For a lot of employees receiving meaningful equity compensation, 22% genuinely isn't enough. But that doesn't make 37% automatically correct either. The right answer depends on your full tax picture, your available cash, how much company stock you actually want to hold, and whether your real priority is minimizing a tax bill, meeting a safe harbor, or something else entirely.

Once shares are sold or withheld, a future refund can't recreate the exact investment position you gave up. Treat this decision as part of your complete financial picture — not a coin flip between two percentages on a screen.

This article is for general educational purposes only and isn't individualized tax, legal, or investment advice. Tax rules, company equity plans, and personal circumstances vary considerably — consult a qualified tax professional before making an equity withholding election.