A year-end tax list for executives, as Mariner Wealth Advisors builds it, has six dated tasks: deferral elections, trading windows, loss harvesting, 401(k) limits, share gifts and estimated payments. Most of those deadlines fall before December 31. Plan deferral elections are often due in November or early December, and the last trading window at many companies closes in mid-December. Only the final estimated tax payment for the year waits until January 15.
We wrote this for executives with RSUs, deferred compensation or a concentrated position in their employer's shares who have a few weeks left and little time. If you're paid straight salary, hold no equity and have no deferral plan, you can skip most of it.
The Mariner Wealth Advisors team wrote it as general education, not tax advice. Start with the table, then read the worked example if you're near Medicare age.
Six year-end deadlines, dated
Read the "who acts" column first. Four of the six tasks depend on someone else (HR, payroll, legal or your broker), so the real deadline is that person's cut-off, not December 31.
Section 409A generally requires deferred compensation elections for next year's salary or bonus by December 31. Many plans shut their election window weeks earlier, and the date is written in your plan's own documents.
Brokers often ask for charitable share transfers two to three weeks before year end. The gift doesn't count until the shares land in the receiving account at the charity or your donor-advised fund.
Your last federal estimated payment for the year falls on January 15, or the next business day if that's a weekend or holiday. It's the one task that runs past New Year's.
| Deadline | Task | Who acts | What to send |
|---|---|---|---|
| Plan window, often November | Next year's deferral election | You, in plan portal | Election form |
| Before last window closes | Company stock sales | You and legal | Preclearance request |
| Final payroll cut-off | 401(k) to $24,500 plus catch-up | Payroll | Deferral change |
| By December 31 trade date | Harvest losses, no wash sale | Advisor | Lot list, replacement fund |
| Broker cut-off, mid-December | Gift of appreciated shares | You and broker | Transfer instructions, DTC number |
| January 15 | Fourth-quarter estimated payment | You or CPA | Form 1040-ES or Direct Pay |
What does moving one distribution across January 1 save? A hypothetical
Moving a taxable distribution from December to January saves the difference between this year's and next year's marginal rate on that income, minus any Medicare premium cost two years later. For Sofia below, the saving is about $7,500 on a $90,000 basis. The decision is also one of timing, not whether to use NUA; our concentrated stock planning work covers that choice.
Hypothetical: Sofia, 63, widowed and recently retired COO of a regional insurer, has no plans to work again. Her 401(k) holds $700,000 of former employer stock with a $90,000 cost basis. She earned most of a year's salary this year, so assume her added income is taxed at 35% this year and 24% next year, for illustration. A December NUA distribution makes her $90,000 basis ordinary income now: $90,000 × 35% = $31,500. A January distribution costs $90,000 × 24% = $21,600, or $9,900 less. The $610,000 of appreciation isn't taxed until she sells either way.
A careful reviewer would run one more check. The $90,000 lifts her MAGI next year from about $60,000 to $150,000, and Medicare uses each year's income to set the premium charged two years later. On the 2026 IRMAA table, that income puts her Part B premium at $405.80 a month instead of the standard $202.90. The extra $202.90 a month × 12 = $2,434.80 a year. Net saving: $9,900 minus $2,434.80, about $7,500.
Plan administrators can take several weeks to process an in-kind distribution of company stock. A lump-sum distribution must also empty the whole account within one tax year, so a request started in December must finish by December 31.
The honest trade-off: the stock stays in the plan a few weeks longer. A 10% move on $700,000 is $70,000, far larger than the tax saving. So the timing only makes sense if she wasn't going to sell the shares right after distribution anyway.
Which tasks apply to you, and who sends what?
Every task applies if you have RSUs, a deferral plan and a 401(k), and each one has a named sender. Treat the table as your routing sheet. Forward each item to its sender today; the last week of December is when payroll and brokers stop taking requests.
Mariner Wealth Advisors sends a lot-by-lot list of unrealized gains and losses before any December trade. Harvesting swaps go into a similar but not substantially identical fund, so the allocation doesn't change.
December sales are tax-lot decisions. They aren't a market call on January.
- You: the deferral election in the HR or plan portal.
- Payroll: the 401(k) percentage change, before the final paycheck's cut-off.
- Legal or compliance: preclearance for any company stock sale, before the window closes.
- Broker: the share transfer instruction, with the receiving charity's or donor-advised fund's account and DTC numbers.
- CPA: a year-to-date tax projection, and the January 15 payment through IRS Direct Pay or Form 1040-ES.
Bunching charitable gifts of shares: what you gain and give up
Bunching means giving two or three years of planned gifts in one year, often through a donor-advised fund, so itemized deductions clear the 2026 standard deduction of $16,100 single or $32,200 married filing jointly. Then you take the standard deduction in the off years.
Here is what you gain and give up.
One rule for the gift itself: sell shares that have lost value and harvest the loss, then give shares that have gained.
- Pro: shares held more than one year are generally deductible at fair market value, and the built-in gain is never taxed.
- Pro: grants to charities can still go out every year from a donor-advised fund.
- Pro: low-basis company stock leaves the portfolio without a sale.
- Con: appreciated stock given to a public charity or donor-advised fund is generally deductible only up to 30% of AGI, with a five-year carryforward.
- Con: off years fall back to the standard deduction.
- Con: a donor-advised fund contribution is irrevocable.
- Con: broker lead times make late-December gifts risky.
How does the list change with age and portfolio size?
The 2026 IRS 401(k) deferral limit is $24,500 under 50. From 50, add an $8,000 catch-up ($32,500 total); at 60 to 63, the catch-up is $11,250 instead. Anyone whose prior-year FICA wages exceeded $150,000, which covers most executives, must make catch-ups as Roth.
At 63 and older, this year's income sets Medicare premiums two years later. Moving income between December and January then needs the IRMAA check shown in Sofia's example.
Once wages stop, as in her case, 401(k) deferrals drop off the list. Distributions, estimated payments and the timing of large income take their place.
Size matters for harvesting. $20,000 of harvested losses against company stock gains at an assumed 23.8% rate cuts tax by $4,760, which is worth the trades. A few hundred dollars of losses in a small taxable account usually isn't.
Is tax-loss harvesting free money? Year-end myths, corrected
No. Harvesting lowers the basis of the replacement fund, so most of the benefit is deferral plus any rate difference. A wash sale, meaning a purchase of the same or a substantially identical security within 30 days before or after the sale, wipes the loss out. RSU or ESPP purchases of the same stock count as buys.
Myth: capital losses can offset salary. Truth: after offsetting capital gains, only $3,000 a year comes off ordinary income, and the rest carries forward.
Myth: December 31 is the deadline for everything. Truth: plan elections and trading windows close earlier, and the estimated payment comes later, on January 15.
Myth: estimated payments are only for the self-employed. Truth: executives with large vests, sales or distributions often need them. Paying 110% of prior-year tax is a safe harbor when AGI was over $150,000.
Timing moves mainly shift tax between years. If your income is about the same every year, they save little. This checklist doesn't replace a CPA's projection or cover state tax rules, which vary. Investing involves risk, including loss of principal.
Questions for your advisor, and what to do this week
The rule for timing is short. If you expect next year's taxable income to be clearly lower, push income you control (a plan distribution, a share sale) into January and keep deductions in December. At 63 or older, first check whether that income crosses a Medicare premium tier two years later.
The costliest slip is asking the broker on December 28 to move appreciated shares to a donor-advised fund. If the shares arrive after December 31, the deduction moves to next year. On a $50,000 gift at an assumed 35% rate, $17,500 of tax savings is delayed by a year, and may be worth less if next year's rate is lower.
Anything that needs a third party gets its request out two weeks before the official deadline.
Mariner Wealth Advisors can run the lot list, check your plan's dates and coordinate with your CPA before the windows close. Our deferred compensation planning and equity compensation advice pages explain how that work goes. Use the request form to ask for a first conversation, held by video or phone.
- Which lots show losses, and what holds the money for the 31 days?
- Should this be a bunching year for gifts?
- Do my withholding and estimates meet a safe harbor?
- Which income should land in January instead of December?
- How does this year's income affect my Medicare premiums two years out?
- This week: check year-to-date 401(k) deferrals on the latest pay stub.
- This week: find the date the last trading window closes.
- This week: ask the broker for its charitable transfer cut-off.
- This week: send the CPA year-to-date income, including vests and sales.
What people ask about a year-end tax checklist for executives
When is the last day a gift of stock to charity counts for this tax year?
Can I still change my 401(k) contribution in December?
Do I need a fourth-quarter estimated tax payment if my employer withholds tax?
What happens if I miss my deferred compensation election deadline?
Can harvested losses offset gains from selling company stock?
Does income I take at 63 affect my Medicare premiums?
Primary sources
This content is general information and education. It is not individual investment, tax or legal advice. Investing involves risk, including the possible loss of principal. Before making any financial decision about your equity awards or assets, consult a professional adviser who knows your full situation.