Year-End Tax Planning for High-Income Business Owners
Most year-end tax tips are noise for a high earner. Buying equipment you do not need or prepaying a few expenses will not dent a serious tax bill. This is the short list of moves that actually move the needle for 2026, ranked by impact, with the real deadline on each one.
By early October, a good CPA is already running a projection of your 2026 tax bill. That projection is the most valuable document you will see all quarter, because it tells you how much room you have to act while there is still time to act. The moves that follow are ordered by how much they can actually save a high-income owner, not by how easy they are, because the easy ones rarely matter and the ones that matter are rarely easy.
A quick framing before the list. Year-end planning splits into two kinds of moves: those that must be fully executed by December 31, and those that can be finalized later, up to your tax filing deadline. Knowing which is which is the difference between a deduction captured and one lost. We will flag the deadline on each.
The Moves That Actually Matter, Ranked
For an owner with strong 2026 income, the size of the available deduction varies enormously by strategy. Here is the honest ranking.
Nothing else on this list is in the same league. A cash balance or defined benefit plan allows an actuarially determined contribution that, for an owner in their 50s or 60s, routinely runs six figures, all of it deductible. The contribution can be funded up to your filing deadline, but the plan design and setup take four to eight weeks, so the decision belongs in Q4. This is the one move where starting late is the same as not starting at all.
See how the numbers scale with age and income in our 2026 cash balance contribution limits table.
If you do not already have a 401(k), the employee deferral piece is the one item here with a true December 31 wall, because deferrals come out of remaining paychecks and cannot be created after year-end. The employer profit sharing contribution on top can wait until your filing deadline. Combined, the 2026 ceiling is $72,000 per participant, or more with catch-up contributions. Owners who also run a pension plan use the 401(k) as the layer that captures the deferral while the pension does the heavy lifting.
If 2026 was unusually strong and 2027 looks lighter, accelerating deductible expenses into December and deferring December invoicing into January can shift income into a lower-rate year. If the reverse is true, do the opposite. This is genuinely useful only when you have a clear read on both years, which is exactly what your Q4 projection gives you. It is a rate-arbitrage move, not a permanent deduction, so it ranks below the plans that remove income entirely.
For S-corporation owners, the split between W-2 salary and distributions affects both payroll tax and how much compensation is available to drive retirement plan contributions. Setting salary too low can cap your pension contribution; setting it purely for tax can invite scrutiny. Q4 is the time to get this right for 2026 and to set it deliberately for 2027, ideally in coordination with whatever retirement plan you are running.
For owners who give anyway, the method matters more than the amount. Donating appreciated securities rather than cash avoids the capital gain, and a donor-advised fund lets you take the full deduction this year while distributing to charities over time, useful for bunching several years of giving into a single high-income year. This is a real strategy, but it reduces a bill you were going to pay to charity regardless, so it sits below the moves that put money back into your own retirement.
Buying equipment you do not need for the write-off, prepaying expenses with no business purpose, or chasing niche credits that take more in fees than they return. For a high earner, these are distractions. The math is simple: one well-designed pension plan can out-deduct every other item on this page combined. Spend your Q4 energy there first.
The Q4 Deadline Map
The single most useful thing to internalize is which moves have a hard December 31 wall and which can be finalized into next year. Here it is in one view.
| Move | Real Deadline | Notes |
|---|---|---|
| Establish a DB / cash balance plan | Design in Q4; fund by filing deadline | Setup takes 4 to 8 weeks, so start now |
| 401(k) employee deferral | December 31, 2026 | Cannot be created retroactively |
| Employer profit sharing | Tax filing deadline + extensions | Decide the amount after year-end |
| Income / expense timing | December 31, 2026 | Must occur within the tax year |
| Charitable gifts (incl. DAF) | December 31, 2026 | Gift must be completed in-year |
| SEP IRA | Tax filing deadline + extensions | Flexible, but limited vs. a DB plan |
| General rules for calendar-year businesses. Extended filing deadlines are typically September 15, 2027 for S corporations and partnerships and October 15, 2027 for sole proprietors and C corporations. Confirm your dates with your CPA. | ||
"The owners who save the most at year-end are not the ones who know the most tricks. They are the ones who started the one big move in October instead of December."
How to Run Your Q4 in Four Steps
-
Get a real 2026 projection from your CPA
Before you can plan, you need the number. Ask for a projected taxable income and tax figure now, in early Q4, while there is still time to act on it. Every decision below flows from that projection.
-
Size the biggest lever first
If the projection shows a large bill, price a defined benefit or cash balance plan immediately. It is the only move that can absorb a six-figure tax problem, and it is the only one with a setup clock that runs against you.
-
Lock the December 31 items
Confirm your 401(k) is in place and your deferral election is set, complete any charitable gifts, and execute any income or expense timing before the year closes. These cannot be fixed in January.
-
Leave the flexible items for the new year
Employer profit sharing and pension funding can be finalized once your books close and the exact numbers are known, up to your filing deadline. Coordinate the timing with your CPA and plan administrator.
Early October is when the projected 2027 retirement limits firm up, which matters if you are designing a plan to run across both years. See our projected 2027 cash balance and defined benefit limits, and the full year-end retirement plan deadline guide for the plan-specific timing.
Frequently Asked Questions
For most high earners it is a defined benefit or cash balance pension plan, which can allow an actuarially determined, fully deductible contribution of $100,000 to $300,000 or more depending on age and income. No other standard year-end move comes close in magnitude, which is why it belongs at the top of any Q4 plan.
Employee 401(k) deferrals, charitable gifts, and income or expense timing must be completed by December 31. Employer profit sharing and pension plan funding can generally be finalized up to your tax filing deadline including extensions. A new pension plan should be designed in Q4 even though funding can wait, because setup takes weeks.
No, but it is the last comfortable window. A cash balance or defined benefit plan takes four to eight weeks to design and establish, so starting in October or early November is sensible. Waiting until December compresses the timeline and risks missing year-end steps.
Only if you actually need the equipment. Spending a dollar to save roughly 37 cents is not a strategy unless the purchase has genuine business value. For a high earner, a retirement plan that shelters income you keep is almost always a better use of the same cash.
Your W-2 salary drives how much compensation is available to fund retirement plan contributions, so setting it too low can cap your pension deduction. It also affects payroll tax. Q4 is the right time to review the salary-versus-distribution split for 2026 and set it deliberately for 2027, ideally alongside your plan design.
Turn Your 2026 Projection Into a Plan
Send us your age, income, and entity type. Our enrolled actuaries will show you the largest deduction still available for 2026 and design the plan to capture it, before the year-end window closes. No cost.
No obligation. No cost. · +1 (646) 409-1660
