A Fourth-Quarter Tax Checklist for Physician Households: What Still Counts Before December 31

It's early October. Open enrollment emails are stacking up, the holidays are already on the call schedule, and somewhere in the back of your mind is a familiar thought: "Is there anything I'm supposed to do with our taxes before the year ends?"

There usually is. But not everything on the year-end list runs on the same clock. Some decisions close on December 31 and can't be revisited. Others look urgent in December but can wait until April. Knowing which is which can take a lot of pressure off a season that's already busy, especially when you're also working through benefits open enrollment for your physician family at the same time.

This is a fourth-quarter tax checklist for physician households, organized by deadline. It's meant to be a map, not a manual. Where a topic already has its own deep dive on our blog, we'll point you there rather than re-explain it, so you can spend your limited evening time on the items that actually apply to your household.

The Two Clocks: December 31 vs. April

For the 2026 tax year, most year-end items fall into two groups. The first group is anything that has to happen inside the calendar year to count: Roth conversions, trades that realize gains or losses, and charitable gifts. The second group is anything the tax code lets you complete after the year ends but still applies to 2026, such as IRA contributions. A few items sit in between, like the fourth-quarter estimated payment, which is due in January.

Several of the December items connect to bigger topics we've covered separately, including Roth conversions after the TCJA "sunset" that didn't happen and tax-loss harvesting in a physician's taxable brokerage account. This article stays focused on timing.

Here's the full checklist at a glance, with the deadline that applies to each item for the 2026 tax year:

The December 31 Items

1. Your 401(k) or 403(b) Deferrals

According to the IRS announcement of the 2026 retirement plan limits, the employee deferral limit is $24,500 for 2026. If you're 50 or older, the catch-up limit is $8,000, and a higher catch-up of $11,250 applies if you're 60, 61, 62, or 63.

If your household had a mid-year job change, a new contract, or a spouse who started a new position, it's worth looking at how much has been deferred so far this year. Your plan administrator or HR team can usually confirm where your 2026 deferrals stand.

2. Roth Conversions

A Roth conversion is reported on your return for the year it's completed. The Instructions for Form 8606 have you report conversions in Part II for the tax year they happened.

Conversions also can't be reversed. The IRS retirement plan FAQs on IRAs note that, effective January 1, 2018, a conversion from a traditional IRA, SEP, or SIMPLE IRA to a Roth IRA cannot be recharacterized. So the decision you make in December is the decision you'll report in April.

For a high-earning attending, the tax cost of a large conversion at a top marginal rate is significant, so conversion conversations tend to come up in specific years: a year with a gap between training and an attending job, a sabbatical or part-time year, a spouse stepping back from work, or the early years of retirement before Social Security and required distributions start. If 2026 looks like one of those years for your household, December is when the numbers are clearest, since you have most of the year's income in hand. A CPA can model how a given conversion amount stacks onto your other income before the year closes.

One timing note on the backdoor Roth: a contribution to a traditional IRA for 2026 generally must be made by the due date of your return, not including extensions, which is April 15, 2027 (see IRS Publication 590-A), but a conversion is reported for the year it actually happens. Form 8606 is the form used to report both nondeductible IRA contributions and conversions, so if you split those steps across calendar years, it's worth confirming that your tax preparer is reporting both correctly.

3. Tax-Loss Harvesting and Gain Decisions in Taxable Accounts

IRS Publication 550 tells readers not to confuse the trade date with the settlement date for stock sold on an established market, which is why a sale generally needs to be executed by December 31 to count for 2026. Per IRS Topic 409, if your capital losses exceed your capital gains, the loss you can claim to lower your income is the lesser of $3,000 ($1,500 if married filing separately) or your total net loss, and a larger net loss can be carried forward to later years.

The rule that trips people up is the wash-sale rule. IRS Publication 550 explains that a wash sale occurs when you sell stock or securities at a loss and, within 30 days before or after the sale, buy substantially identical stock or securities, or acquire substantially identical stock for your IRA or Roth IRA (Revenue Ruling 2008-5 addresses the IRA case). It also says that if you sell stock and your spouse or a corporation you control buys substantially identical stock, you have a wash sale.

Harvesting a loss is a tax decision, not a prediction about where any investment goes next. Whether harvesting makes sense depends on your current gains, your bracket, and how the replacement investment fits your overall allocation. We go deeper into what tends to matter in the tax-loss harvesting article linked above.

4. Charitable Gifts and Donor-Advised Fund Timing

According to IRS Publication 526, a check you mail to a charity is considered delivered on the date you mail it, and contributions charged on your bank credit card are deductible in the year you make the charge.

2026 brings changes to charitable deductions. According to IRS Publication 505 for 2026, if you itemize, you can only deduct charitable contributions that are more than 0.5% of your adjusted gross income. On a household AGI of $500,000, for example, the first $2,500 of giving wouldn't be deductible. The same publication also describes a separate reduction in itemized deductions that applies when taxable income is above certain thresholds.

If you don't itemize, there's something new for you too. Beginning with tax year 2026, the IRS says individuals who don't itemize may deduct up to $1,000 of cash contributions to eligible charitable organizations ($2,000 for married taxpayers filing jointly), and that donations to donor-advised funds and supporting organizations do not qualify (see the IRS summary of the 2026 changes).

These changes may affect how you think about timing. Some physician households "bunch" several years of giving into one year through a donor-advised fund, then grant to charities over time. The 2026 floor may change the math on that approach compared with prior years, so it's a conversation worth having with your CPA before you write the check. Our article on donor-advised funds and bunching charitable gifts walks through how bunching works.

5. Health FSA Balances: Use It or Lose It (Mostly)

According to IRS Publication 969, FSAs are generally "use-it-or-lose-it" plans, but a plan can provide for either a grace period of up to 2 1/2 months after the end of the plan year or a carryover. The IRS 2026 inflation adjustments set the 2026 health FSA contribution limit at $3,400 and the maximum carryover at $680.

Practically, this item is a quick check: log in, see what's left, and look at what your plan allows.

The Item That Settles in January: Estimated Payments and Withholding

If you make estimated tax payments, IRS Publication 505 lists the fourth payment for 2026 as due January 15, 2027. That falls after year-end, but the decision about how much to pay can be made in December, when your year's income is mostly known.

If you also have W-2 income, or your spouse does, there's a second option. You can increase federal withholding on your final paychecks of the year by updating your Form W-4. The instructions for Form 2210 describe treating federal income tax withheld as if it had been withheld evenly throughout the year. Your CPA can tell you how the Form 2210 treatment applies to your situation.

Which approach fits your situation depends on the safe-harbor rules. Our safe-harbor guide to quarterly estimated taxes for physicians with 1099 income covers how those tests work.

The Items That Can Wait Until April

These are the items that often feel urgent in December but don't have to be. That doesn't mean they should be forgotten. It just means they can come off the December list if your holiday weeks are already full.

• IRA contributions, including the backdoor Roth contribution. The 2026 IRA limit is $7,500, with an additional $1,100 catch-up at 50 or older. Per Publication 590-A, a contribution for 2026 generally must be made by the due date of your return, not including extensions.
• HSA contributions. Publication 969 says you can make contributions to your HSA for a year through the following April 15 (for 2025, through April 15, 2026), and that amounts an employer contributes to employees' HSAs, including amounts employees elect to contribute through a cafeteria plan, aren't generally subject to employment taxes.
• SEP-IRA contributions for 1099 income. The IRS page on SEP plans notes that you can set up a SEP for a year as late as the due date (including extensions) of your business income tax return for that year, and that employer contributions must be made by the due date (including extensions) for filing your federal income tax return for the year.

529 Contributions and Your State

The IRS says contributions to a 529 plan are not deductible on your federal return. Whether your state treats them differently is something to check with your state's 529 plan and your CPA.

If you moved during 2026 for a new attending job, your state's 529 plan website or state tax agency is a good place to check how contributions are treated, and your CPA can tell you how that fits with the rest of your return.

What This Checklist Often Looks Like in Practice

Here's an example of how this tends to come together. Picture a dual-income household: a hospitalist on W-2 salary with a few weekends of locums work, and a spouse who works part-time. In October, they sit down for an hour. The hospitalist's deferrals are on pace to fall short of the $24,500 limit, so they look at whether to raise the percentage on the remaining paychecks. Their taxable account has a fund showing a loss and another showing a large gain, so they ask their CPA which combination makes sense for 2026 and check the dividend reinvestment settings. They've been talking about funding a donor-advised fund, and with the new 0.5% floor, they want their CPA to run the numbers both ways before deciding.

Then they look at what can wait. The backdoor Roth contribution and the HSA deposit go on the list of items that can wait until the April deadline. The locums income means the fourth estimated payment is due in January, but they decide to ask their tax preparer about increasing withholding on the hospitalist's December paycheck instead.

Nothing about that hour is complicated. But it turns a vague year-end worry into a short, dated list, and it puts the December-only decisions in front of the people who need to weigh in on them while there's still time.

Why Coordination Matters More Than Any Single Item

Most of these items interact. A Roth conversion raises your income, which may change what your estimated payment should be. A harvested loss may offset a gain you realized earlier in the year, or it may offset part of the income from a conversion.

That's why the year-end list tends to work best as one conversation rather than five separate ones. When your CPA, your financial planner, and your household are looking at the same projected 2026 numbers, it's easier to see which December decisions matter for your situation and which can wait.

A Conversation Before the Calendar Runs Out

If you'd like help sorting your own year-end list into "before December 31" and "it can wait," we're happy to talk it through. We've spent twenty-five years working with physician families, and we'd be glad to learn about yours and see whether we're the right fit. You can start a conversation with our team here, or email us at contact@physicianfamily.com and we'll find a time that works around your schedule.

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