Year-End Tax Strategy Beyond Section 179. Smart Dentists Know These

The 2026 Section 179 limit is $2,560,000. Nobody reading this is going to use it, and that gap is the most expensive misunderstanding in dentistry's year-end tax planning. IRS Publication 946 sets the maximum expensing deduction at $2,560,000 for tax years beginning in 2026, with the phase-out starting once qualifying property placed in service exceeds $4,090,000. Those are the numbers your equipment rep will quote you in November. They are also completely irrelevant to a practice that nets a few hundred thousand dollars, because the deduction is capped by your business taxable income, not by the statute.

Our view: for a profitable practice, Section 179 is the least valuable year-end tax tool on the table, and if your December plan centers on buying a CBCT you weren't going to buy in March, your advisor is selling you a purchase dressed up as a strategy. A deduction is not a discount. It's the IRS offering to split the loss with you, and you still pay the bigger half.

A $2,560,000 Ceiling in a $215,320 Room

Average 2025 net income for a general-practice dentist in private practice was $215,320, according to the ADA Health Policy Institute. The same research describes a five-year fiscal squeeze: revenue grew 1.4% while expenses grew 4.9%. Read those two numbers together and the picture is a profession whose top line is flat and whose cost base is compounding against it.

That changes what year-end planning is for. When margins were widening, overpaying tax by a few thousand dollars was an annoyance. When expenses are outrunning collections by 3.5 points a year, the tax line is one of the few large costs you can still move with a decision rather than a renegotiation. And the move that actually matters is not the one with a dealer invoice attached.

Here is the scale problem. A dentist netting $215,320 who buys a $130,000 scanner in December has committed about 60% of a full year's income to a purchase whose tax benefit is a fraction of that. The Section 179 ceiling of $2,560,000 is set for manufacturers and multi-site groups placing millions in service. You are operating in a room where the binding constraint is your own taxable income, and Publication 946 is explicit that the expensing deduction cannot exceed it. Any excess just carries forward, which means the "write it all off this year" pitch quietly becomes "write some of it off over several years" the moment the purchase gets large.

The December Scanner Costs You $81,900

Run it. Assume you're in the 37% federal bracket, ignore state tax for a moment, and buy a $130,000 piece of equipment on December 20 purely for the deduction.

The full $130,000 is expensed, and at a 37% marginal rate that saves $48,100 in federal tax. Your cash position after the dust settles is down $81,900. You own an asset you didn't plan for, you've consumed depreciation you might have wanted in a higher-income future year, and if you financed it, you've added a monthly payment to a practice whose expense growth is already the problem.

Now the same owner, same bracket, funds retirement instead. The 2026 elective deferral limit for 401(k) plans rises to $24,500, with an $8,000 catch-up at age 50 and over, per the IRS newsroom announcement. That's $32,500 of deferral for an owner over 50. Stack a cash balance plan on top of it. Say your actuary certifies a $165,000 owner contribution for a 54-year-old at your compensation level, which is the kind of number these plans produce for an older, high-earning owner. Total deductible contribution: $197,500. At 37%, that's $73,075 of federal tax deferred.

The difference between the two is not the tax saved. It's where the money lives afterward. The scanner scenario leaves $81,900 permanently gone from your household. The retirement scenario leaves $197,500 sitting in an account with your name on it, minus two real costs: the staff contributions required to pass testing, call it $22,000, which costs $13,860 after the deduction , and roughly $4,500 in actuarial and administration fees, or $2,835 after tax. Total real cost to move $197,500 off your taxable income and onto your own balance sheet: about $16,695.

We'd skip the scanner. The ceiling on this strategy is generous: the IRS caps a defined benefit plan's annual benefit for 2026 at the lesser of 100% of the participant's highest three-year average compensation or $290,000, which is what makes six-figure annual shelter possible for an owner in their fifties.

Where Most Owners Get It Wrong: Confusing a Deduction With a Discount

The specific mistake is treating the write-off percentage as the win. It shows up most often in owners aged 45 to 60 with a paid-off or nearly paid-off practice, strong collections, and a CPA who files returns but doesn't plan. Those owners are told in late November that they're "going to get killed on taxes," and the only tool anyone puts in front of them is equipment. So they buy. Every December. For a decade.

Our view: write-off percentage is the wrong metric entirely. The right one is how many cents of each dollar you spend stay yours. On a deductible equipment purchase at a 37% rate, zero cents stay yours; you've converted cash into a depreciating asset and received 37 cents back. On a retirement plan contribution, 100 cents stay yours and you receive the same 37 cents of tax relief. On a cost segregation study, you spend a few thousand dollars in fees to accelerate deductions you already owned.

The second version of this mistake is deduction timing. Expensing $130,000 today at a 37% rate, when you intend to sell the practice in four years and will likely have an unusually high-income year on the transition, trades a 37-cent deduction for one that could have been worth more later. Nobody sells you that conversation, because nobody earns a commission on it.

42% of Your Building Isn't a 39-Year Asset

If you own your building, or own the entity that owns it, this is the move most practice owners have never had explained. The default is to depreciate the whole structure over 39 years. An engineering-based cost segregation study breaks the building into its components and reassigns the ones that are legally shorter-lived.

In a cost segregation study on an actual dental clinic, 32.77% of the depreciable basis, or $109,403.70, was reclassified to 5-year property, and 9.95%, or $33,235.11, moved to 15-year property. That's over 42% of the building accelerated out of the 39-year schedule. Back into the basis and you get a building of roughly $334,000.

On the standard schedule, $334,000 over 39 years is about $8,564 of depreciation a year. After reclassification, the 5-year bucket throws off roughly $21,881 a year , the 15-year bucket about $2,216 , and the remaining $191,361 of long-life basis about $4,907. Annual deduction in the first five years: roughly $29,004 instead of $8,564. That's $20,440 of additional deduction per year , worth about $7,563 a year at a 37% rate , or $37,815 across five years. If the study costs $9,000, you're up well into five figures on a building you already own, having bought nothing.

Two honest caveats. This is timing, not magic: accelerated depreciation on personal property comes back as recapture when you sell, so the value is the use of the money in between plus the rate difference. And ask your CPA specifically whether bonus depreciation applies to the reclassified short-life property in your placed-in-service year, because it moves the first-year number materially and the rules have been a moving target.

Three Moves With No Invoice Attached

None of these require buying equipment, and most practices leave at least one on the table.

• Cash-basis timing. Most practices file cash basis. That makes the last two weeks of December a dial: when you deposit collections, when you pay vendors, when you run the staff bonus. Moving a payable from January 3 to December 29 is a deduction this year at this year's rate.
• Accountable plan reimbursements. If you've been personally absorbing mileage, home office, or CE travel costs with no written reimbursement policy, you're donating deductions. Get the plan documented and reimburse before year-end.
• Owner compensation review. If you're an S corporation, the split between W-2 wages and distributions drives both your tax bill and the size of the retirement contribution you're allowed to make. Those two decisions are linked, and most owners set the wage once and never revisit it.

A cash balance plan, to be clear, is not a one-December decision. It's a funding commitment you should expect to carry for several years, with contributions that flex within a range but don't go to zero on a whim. If your collections are volatile or you're 18 months from selling, that commitment is the wrong shape and we wouldn't take it on.

What Would Change Our Mind

If a piece of equipment genuinely adds production, buy it, and buy it in whatever month the economics say. A CBCT that brings implant and endo work in-house is a growth decision that happens to be deductible, and that's a different conversation from the one happening in most practices on December 18. We're watching two things into next year: whether bonus depreciation treatment on reclassified short-life property holds, since that's what determines if cost segregation is a strong play or an overwhelming one, and whether the ADA's expense-growth line bends. If expenses keep compounding at 4.9% while revenue crawls, the next frontier isn't the tax code at all. It's your payer mix.

Four Calls to Make Before December 15

Call your CPA and ask one question: what's my projected taxable income, and what's the marginal rate on the last dollar? Then call a third-party administrator about a cash balance plan illustration using your actual payroll census, not a brochure example. If you own your building, get one cost segregation quote and compare the fee to five years of the extra deduction. Last, document your accountable plan and run the reimbursements before the calendar closes.

Before you decide how to shelter your profit, make sure you know how much of it the practice is actually keeping. The expense side is where the squeeze is happening, and a tax plan can't fix a 68% overhead problem. Pull your last twelve months of collections and expenses and run your own numbers through our overhead calculator to see where your margin sits against practices your size. Knowing that figure is what tells you whether this year's conversation is about tax strategy or about cost control.