Why is my tax bill bigger than I expected

Why is my tax bill bigger than I expected?

If you received a severance payment and later found you owed more tax than you planned for, you are not alone, and you did not do anything wrong. The gap comes from the way severance is taxed at the moment it is paid, which is different from the way your regular paycheck is taxed. Understanding that difference ahead of time is the whole game, because the surprise almost always arrives in April, long after the money is spent.

Withholding is not the same as what you owe

Start with the distinction that causes the confusion. The tax withheld from a payment is a prepayment toward your final bill. It is an estimate. What you actually owe is settled later, when you file, based on your total income for the year. Most of the time those two numbers land close enough that people never think about the difference. With severance, they often do not.

Severance is generally treated as supplemental wages, a category that also includes bonuses and commissions. Supplemental wages are frequently withheld at a flat federal rate rather than at the rate your regular salary uses. For many people, especially higher earners, that flat withholding rate is lower than the marginal rate their income actually lands in. The money is withheld as if it will be taxed at one rate, and then at filing it is taxed at your real rate, which is higher. The difference is the bill that surprises people.

In plain terms, more was handed to you up front than will turn out to have been yours to keep, and the balance comes due later.

Why a layoff makes the gap worse

The timing of a layoff can widen the gap in a way that catches people off guard.

If you are laid off partway through the year, you have already earned months of regular salary at your normal withholding. Then the severance lands on top of that. Depending on the size of the package, that combined total can push part of your income into a higher bracket than your salary alone would have reached. The severance was withheld at the flat supplemental rate, but stacked on top of a full or partial year of earnings, part of it is taxed at your top marginal rate. The stacking is what turns a modest gap into a real one.

If any equity accelerated when you left, or you exercised options, that income can stack in the same year as well, compounding the effect. Several kinds of income can converge into a single tax year, each withheld as if it stood alone, all taxed together at the end.

Why people get caught

The reason this surprises careful people is that nothing in the process warns them. The severance arrives, the withholding looks like a large number, and it is reasonable to assume the tax was handled. The money goes into the household, or toward the runway, or toward the search. Then the return is prepared months later, the total income is added up, the real rate is applied, and the balance appears at a moment when income has already stopped and every dollar matters more.

It is not a mistake of carelessness. It is a mismatch between when the money arrives and when the tax is actually settled, and the mismatch is invisible unless someone points it out in advance.

What to actually do about it

The fix is to close the gap on purpose, before it becomes a surprise.

Estimate your real tax picture for the year rather than trusting the withholding to have covered it. That means looking at your total expected income for the year, all sources together, and comparing what you will actually owe against what has been withheld so far. If there is a shortfall, you want to know the size of it while you still have the severance in hand, not after it is gone.

This is a place where your CPA earns their fee, and it is exactly the kind of thing I work through with clients and their accountants together. When the numbers are significant, I get on a call with your CPA, one of us watching the planning and one watching the return, and we look at whether additional withholding or an estimated payment makes sense, and whether any of the timing choices elsewhere in your package can reduce the total. The tax you owe is largely fixed by the rules, but the surprise is optional. The surprise comes from not knowing the number. Once you know it, you can set money aside, adjust withholding, or make an estimated payment, and the April bill stops being a shock.

Sometimes you can move the payment itself

Knowing your number is the first step. Sometimes there is a second one: changing which year the money lands in.

If you are laid off partway through a year in which you have already earned a full or partial salary, your severance is stacking on top of a high-income year. But if the payment could instead land in the following year, and your income in that following year is going to be lower, the same dollars can be taxed in a lower bracket. Some employers will allow a one-time severance payment to be scheduled into the next tax year. It is not always possible, and it depends on the plan and the agreement, but it is worth asking before anything is signed, because once the payment date is set it is usually fixed.

This matters most for someone who is not planning to go straight back into full-time work. If you are retiring, taking an extended break, or moving into something that pays less, next year may be a genuinely low-income year, and shifting the payment into it can make a real difference. I have worked through exactly this with clients, looking at whether the payment could move and what it would save, in the same year the timing on other pieces of the package came into play.

This is planning that happens between me and your CPA, not something to guess at alone. One of us is watching the tax return and one is watching the full financial picture, and together we work out whether moving the payment helps, and by how much, before the decision is locked. The timing question has to be asked early, though, because the window to change a payment date closes the moment the paperwork is final.

Specific rates, thresholds, and current-year figures change, so I keep those on a separate page that I update rather than putting them here where they would age. What does not change is the mechanic: severance is often withheld light, it stacks on the rest of your year, and the difference is settled when you file. Plan for that and the surprise goes away.

If you want to see your real tax picture for the year before the bill arrives, that is work I am glad to do with you and your accountant. Start a conversation.

This material was created to provide accurate and reliable information on the subjects covered but should not be regarded as a complete analysis of these subjects. It is not intended to provide specific legal, tax or other professional advice. The services of an appropriate professional should be sought regarding your individual situation. 

Riverstone Wealth Planners and LPL Financial do not provide legal or tax advice. Please consult with your tax or legal advisor regarding your personal situation.