Year-end tax planning: what should high earners do in Q4?
Every fall, the same conversation shows up in our Los Angeles office. A client walks in with a K-1 they were not expecting, an ISO exercise their broker just processed, a bonus that pushed them past a surtax threshold, or a real-estate deal that closed in November. They want to know what they can still do about it before the calendar turns. Year-end tax planning is the answer, and for high earners the window is narrower than most guides admit. The moves that meaningfully change the tax bill are almost all keyed to a December 31 event: a payroll withholding cut, a broker settlement, a check clearing a qualified charity, a gift completed under Section 2503. Miss the date and the strategy goes with it.
This post walks through the seven year-end levers that our practice actually reaches for, anchored to the IRS primary sources that govern them. We use the current-year IRS-published limits rather than reciting numbers that will be outdated by the time you read this — the linked IRS pages carry the figures that count. The point is to give a high-income taxpayer a decision-quality checklist, not a generic overview.
Why is Q4 the last window that matters for year-end tax planning? 📅
Because most of the moves that change a high earner’s return are keyed to a December 31 event — a payroll withholding, a broker settlement, or a completed transfer. After January 1 those levers are closed for the prior year.
A useful way to see the fourth quarter is as a series of one-way doors. The 401(k) elective deferral runs off the last payroll cycle of the year, not the calendar. A tax-loss harvest depends on the trade date, not the settlement statement you receive in January. An incentive-stock-option exercise is a December 31 measurement date for the AMT preference. An annual-exclusion gift is either delivered by December 31 or it is not made in 2026 at all. See the IRS 2026 inflation adjustments for the year’s threshold amounts.
What makes the window narrow for high earners specifically is the surtax and phase-out geography. Once modified adjusted gross income crosses the net investment income tax threshold under Section 1411, the additional Medicare tax threshold under Section 3101(b)(2), the Section 199A phase-out, or the individual AMT exemption phase-out, every incremental dollar is taxed harder than the marginal bracket suggests. The Q4 job is to see which surtax you are on the edge of, then choose the tool that moves you back across the line.
How much can high earners actually save into 401(k)s and IRAs before Dec 31? 💼
Up to the IRS-published elective deferral and catch-up amounts for the year, plus additional room for the self-employed through a solo 401(k) or SEP-IRA. Fund it through payroll by the last cycle of the year for W-2 income; IRA and self-employed retirement plans usually have a later deadline.
The three retirement levers that matter most in Q4:
- Elective deferrals. Check with payroll that you are on pace to hit the current year’s elective deferral limit by the last check in December. Roll off catch-up if you are 50 or older. If you were between ages 60 and 63 at year-end, confirm your plan implemented the SECURE 2.0 expanded catch-up. Current figures are on the IRS 401(k) contribution limits page and the IRS catch-up contribution rules page.
- Solo 401(k) and SEP-IRA. Self-employed high earners can shelter meaningfully more than a W-2 employee at the same income level because the employer contribution is available. The plan usually must exist by December 31; the funding deadline can extend to the return due date with extensions. If a solo 401(k) is new, set it up before year-end.
- Defined benefit and cash balance plans. For owner-only businesses with strong cash flow, these can allow contributions well into the six figures. They require an actuarial certification and an adoption deadline that lands, in most cases, before the return due date. If the idea is not already scoped by early Q4, it usually will not happen for this year.
Catch-up contributions and the Roth requirement
Under SECURE 2.0 as amended, catch-up contributions by employees whose prior-year FICA wages exceed the statutory threshold must be designated as Roth contributions if the plan permits catch-ups at all. If your plan has not yet added a Roth catch-up feature, confirm before December that your catch-up is not silently ineligible.
When does tax-loss harvesting help — and when does the wash-sale rule undo it? 📉
Selling positions at a loss before December 31 can offset realized capital gains and, up to $3,000 a year, ordinary income. But 26 U.S.C. § 1091 disallows the loss if you buy the same or substantially identical security within 30 days before or after the sale.
The wash-sale rule is the single most common way high earners accidentally lose the loss they thought they harvested. IRS Publication 550 lays out the mechanics: sell XYZ at a loss on December 15, buy XYZ back on December 20, and the loss is disallowed and added to the basis of the December 20 shares. The 61-day window covers 30 days on either side of the sale, so a purchase inside your IRA or your spouse’s account can trigger the rule too.
Two practical patterns keep the loss and keep the market exposure:
| Approach | How it works | What to watch |
|---|---|---|
| Rotate into a similar, not identical, fund | Sell an S&P 500 ETF, buy a broad-market or total-stock-market ETF for 31 days, then rotate back. | “Substantially identical” is a facts-and-circumstances test. Two funds tracking the same index are generally treated as identical. |
| Wait out the 30-day window | Sell the loss position, hold cash or a short Treasury fund for 31 days, then re-enter. | Market movement risk during the 31 days. Sometimes this is the honest cost of the loss. |
| Coordinate spouse and IRA accounts | Suspend automatic dividend reinvestment and any recurring buy programs in identical securities across all household accounts for the 61-day window. | Wash sales from an IRA are especially costly — the loss is disallowed and there is no basis recovery inside the IRA. |
How do incentive stock options and NQSOs change year-end tax planning? 📈
An ISO exercise is a December 31 measurement date for the AMT preference; an NQSO exercise is ordinary income on the spread at exercise, regardless of when you sell. Deciding when to exercise is often the largest single year-end lever a high earner has.
For an ISO, the spread between the strike price and the fair market value at exercise is not ordinary income for regular tax, but it is an AMT preference item under Section 56. In a high-income year with a large exercise, the AMT can be the actual tax you owe. IRS Topic 556 (Alternative Minimum Tax) walks through the structure. The classic pattern is to size the exercise so that regular tax and tentative minimum tax meet at the exemption edge — anything more crosses into AMT territory and the additional shares are taxed twice unless you hold long enough for the AMT credit to recover.
NQSOs are the opposite problem. The spread is ordinary income at exercise and shows up on Form W-2, so a large exercise in a high-income year stacks on top of your bracket. If you already know you will exercise a block of NQSOs, splitting the exercise across a December-and-January boundary sometimes keeps you out of a surtax that would otherwise catch the full amount. IRS Publication 525 covers the reporting mechanics for both ISOs and NQSOs, and for restricted stock and RSUs.
From our practice: model AMT before the exercise, not after
In our practice, the ISO exercises that go badly are almost always the ones that were sized against a target number of shares rather than a target AMT number. Run a two-scenario AMT projection in early December — one at the intended exercise size, one at the size where regular tax equals tentative minimum tax — and let the delta decide how much of the block to exercise this year versus early next year.
How can charitable giving and gift tax exemptions cut the 2026 tax bill? 🎁
Three moves do most of the work: donating appreciated securities instead of cash, using a donor-advised fund to bunch several years of giving into a single high-income year, and, for IRA owners aged 70½ or older, running gifts through a qualified charitable distribution.
- Appreciated securities to a public charity. Under Section 170, a gift of long-term appreciated stock to a qualifying public charity is generally deductible at fair market value, and the built-in gain is never taxed to the donor. For a high earner sitting on a low-basis position, this is dollar-for-dollar more valuable than giving cash and selling the shares.
- Donor-advised fund bunching. A DAF lets you take the deduction this year for a block that will be distributed to charities over several years. Bunching multiple years of giving into a single high-income year, funded with appreciated stock, can push you well over the standard deduction only in the years where the marginal tax value is highest.
- Qualified charitable distributions. If you are 70½ or older, direct up to the annual IRS limit from your IRA to charity as a QCD. It counts toward your required minimum distribution and is excluded from gross income — see IRS qualified charitable distribution rules and IRS Publication 590-B. Because it never enters AGI, it can protect Social Security taxation, IRMAA, and NIIT thresholds in ways an itemized deduction cannot.
- Annual-exclusion gifts. For 2026, gifts up to $19,000 per recipient use none of your lifetime exemption. A married couple electing gift-splitting can move $38,000 per recipient. This is the simplest generational transfer available and it resets every January 1.
- Lifetime estate and gift exemption. The federal estate and gift tax exemption for 2026 is $15 million per individual, or $30 million for a married couple. If your estate is over the threshold, larger year-end transfers — GRATs, spousal lifetime access trusts, family limited partnerships — deserve a specialist review. The official current-year figure lives on IRS estate and gift tax updates.
Do the gift by December 31, not on paper
A gift of stock is completed when the transfer is recorded on the books of the issuer or custodian, not when you sign the letter of instruction. December 31 falls on a Thursday in 2026 and clearing systems slow around the holidays. Initiate transfers by mid-December so the shares actually settle in the recipient’s account this calendar year.
What year-end tax planning moves should high earners not miss? ✅
Project your taxable income and AMT before December 1, decide which surtax you are closest to, and choose the single largest lever that moves you back across the line. Everything else on the checklist is second-order.
- Project taxable income and AMT before December 1. Pull year-to-date W-2, K-1, and 1099 information. Add expected bonuses, RSU vests, and closing gains. The number decides everything else.
- Max out elective deferrals through the last payroll of the year. Add the catch-up if age-eligible; confirm the Roth catch-up mechanics if your plan has that requirement.
- Harvest losses with the wash-sale calendar in front of you. Note the 30-day windows across all household accounts. Suspend recurring buys in identical securities.
- Size any ISO or NQSO exercise to a modeled AMT and bracket number, not a share count. Split blocks across the year boundary when it saves a surtax.
- Fund a donor-advised fund with appreciated stock, not cash. Take the deduction this year; grant it out over multiple years.
- Run large charitable gifts through a QCD if you are age 70½ or older. It removes the amount from AGI, not just from taxable income.
- Complete annual-exclusion gifts and larger transfers by mid-December. The transfer, not the letter of instruction, has to settle in the calendar year.
Summary: Q4 year-end tax planning for high earners
- Most levers that shift a high earner’s return close at midnight on December 31 — retirement deferrals, wash-sale-safe loss harvests, stock-option exercises, QCDs, and annual-exclusion gifts.
- Use the IRS-published limits for the year (401(k), IRA, catch-up, QCD, annual-exclusion gift, estate exemption). The linked IRS pages carry the current figures.
- The wash-sale rule under 26 U.S.C. § 1091 disallows losses when substantially identical securities are bought within a 61-day window — coordinate across spouse and IRA accounts.
- For ISOs, size the exercise to a modeled AMT number, not a share count. For NQSOs, splitting the exercise across the year boundary sometimes saves a surtax.
- A QCD for taxpayers 70½ or older beats an itemized charitable deduction because it never enters AGI, protecting IRMAA, Social Security taxability, and NIIT thresholds.
Frequently asked questions about year-end tax planning ❓
Q. When does the window for year-end tax planning actually close?
For most federal moves that affect your 2026 return, December 31 is the hard deadline. Selling a losing position for a wash-sale-safe tax loss, exercising incentive stock options, funding most workplace retirement plans, making a qualified charitable distribution from your IRA, and completing annual-exclusion gifts must all be finished by year-end. A handful of items — traditional and Roth IRA contributions, HSA contributions, and SEP-IRA funding for the self-employed — can be made up to the following April, but everything driven by a payroll withholding or a broker settlement date needs to happen well before December 31.
Q. Should high earners defer income to 2027 or accelerate it into 2026?
It depends on where each dollar lands on the bracket table. If your 2026 marginal rate is unusually high because of a business sale, a large bonus, or an option exercise, deferring the next chunk of income (a year-end bonus, a consulting invoice, a Roth conversion) to 2027 can save real money. If 2027 looks higher — a planned exit, a bracket-driving inheritance, or expiring credits — the opposite is true. The trap is deferring for its own sake. Model both years, watch the AMT line, and let the numbers decide.
Q. What does the IRS actually let me contribute to a 401(k) and IRA?
The IRS publishes the elective deferral and catch-up limits each fall, then indexes them to inflation. For the current year, check the IRS 401(k) and profit-sharing plan contribution limits page and the catch-up contribution page linked in the article. If you are age 50 or older, you get a standard catch-up. Under SECURE 2.0, workers aged 60 through 63 get a larger, temporary catch-up. Self-employed high earners with a solo 401(k) or SEP-IRA can shelter meaningfully more than a W-2 employee at the same income level.
Q. How does the wash-sale rule undo my year-end tax-loss harvesting?
Section 1091 of the Internal Revenue Code disallows a loss on the sale of stock or securities if you buy substantially identical securities within 30 days before or 30 days after the sale. The disallowed loss is not lost forever — it is added to the basis of the replacement position — but it does not offset gains this year. IRS Publication 550 explains the mechanics and the 61-day window. To keep market exposure without triggering the rule, high earners commonly rotate into a similar-but-not-identical fund or a different-issuer bond and wait out the window.
Q. What is a qualified charitable distribution and who benefits most?
A qualified charitable distribution, or QCD, is a direct transfer from a traditional IRA to a qualified public charity. If you are age 70½ or older, a QCD counts toward your required minimum distribution and is excluded from gross income, capped annually at the amount the IRS publishes (see the QCD page linked in the article). Because it comes out before it is ever reported as income, a QCD reduces AGI-linked items — Medicare IRMAA, the taxability of Social Security, the net investment income tax threshold — in a way an itemized deduction cannot. It is the strongest year-end move for retirees who otherwise take the standard deduction.
Q. How much can I give without touching my lifetime estate exemption?
The annual gift tax exclusion for 2026 is $19,000 per recipient. A married couple electing gift-splitting can move $38,000 per recipient without filing Form 709 or using any of the lifetime exemption. On top of that, the federal estate and gift tax exemption for 2026 is $15 million per individual and $30 million for a married couple, following the changes made by the 2025 tax act — see the IRS estate and gift tax page linked in the article for the official figure. Annual-exclusion gifts made in December are the simplest generational transfer available; they reset every January 1.
This article is general information, not tax or legal advice for your situation. Year-end tax planning turns on facts — income sources, plan documents, and the interaction of federal and state rules — that vary by client. Contact SW Accounting & Consulting Corp for a confidential Q4 review before December 15.
