"Buy It Before December 31st and Write It All Off!" Not So Fast: How Section 179 Really Works in 2026

Normally, when your business buys equipment, you don't deduct the full cost in the year you buy it. You depreciate it, spreading the deduction over the asset's useful life. Section 179 lets you elect to expense the cost of qualifying property in the year it's placed in service, instead of depreciating it over several years.

For tax years beginning in 2026, the maximum Section 179 deduction is $2,560,000. That limit is reduced dollar for dollar once the total cost of Section 179 property you place in service during the year exceeds $4,090,000. Those are big numbers, and most small businesses will never get near them. That's exactly why people assume there's no catch. There is.

Not Actual Tax Law: Buy as much as you want, deduct all of it, and if it produces a big loss, even better.

Actual Tax Law: The Section 179 deduction is limited to your taxable income from the active conduct of trades or businesses. It cannot create or increase a loss. Any amount you can't use because of this limit isn't lost; it carries forward to future years, but it doesn't help you this year.

Here's the part many people miss: that income limit is measured using the aggregate taxable income from all of your active trades or businesses, not just the business that bought the equipment. And W-2 wages count as income from the active conduct of a trade or business for this purpose. So if your side business barely breaks even but you (or your spouse, on a joint return) earn W-2 wages, that wage income can help absorb a Section 179 deduction. On the flip side, if your only business had a rough year and you have no other active business income or wages, Section 179 may do far less for you in 2026 than you expected.

Not Actual Tax Law: As long as the invoice is dated in 2026, you get the deduction for 2026.

Actual Tax Law: The property must be placed in service by December 31. That means it's ready and available for its intended use in your business. A machine still sitting in a crate in the warehouse, a truck on back order, or a computer that hasn't been set up doesn't qualify for 2026, no matter when you paid for it.

If you're shopping in late December, confirm delivery dates and plan for installation time. Keep the delivery receipt, the installation records, and anything else that shows when the asset actually went into use.

Not Actual Tax Law: If it's a business asset some of the time, you can deduct the whole thing.

Actual Tax Law: You can deduct only the business-use percentage. If a piece of equipment is used 70% for business and 30% personally, only 70% of the cost is eligible. And to use Section 179 at all, the property has to be used more than 50% for business in the year it's placed in service.

It doesn't stop there. If business use later falls to 50% or below during the asset's recovery period, part of the deduction you previously took is recaptured, meaning it's added back to your income. A big deduction this year can turn into a surprise tax bill a couple of years from now. Keep usage records, especially for vehicles, computers, and anything that comes home with you.

Not Actual Tax Law: Any vehicle you buy for the business is fully deductible in year one.

Actual Tax Law: Vehicles have their own set of rules, and which rules apply depends heavily on the vehicle's weight.

Passenger automobiles (generally 6,000 lb gross vehicle weight rating or less) are subject to the Section 280F "luxury auto" depreciation caps. For passenger automobiles placed in service in 2026, the first-year limit is $20,300 if bonus depreciation applies, or $12,300 if it doesn't. So that pricey sedan doesn't produce anywhere near a full write-off in year one.

Heavy SUVs (over 6,000 lb GVWR, up to 14,000 lb) are exempt from the Section 280F caps, which is where the "buy a big SUV" advice comes from. But they're not unlimited under Section 179 either. They have their own separate Section 179 SUV limit, which is $32,000 for tax years beginning in 2026. Certain vehicles, like some pickups with a long enough bed, cargo vans without rear seating, and vehicles seating more than nine passengers behind the driver, are excluded from the SUV definition and aren't subject to that cap.

The business-use percentage and recapture rules still apply on top of all of this. A $100,000 SUV used 60% for business is a $60,000 depreciable basis, before any limits even come into play.

Section 179 isn't the only way to accelerate a deduction. Bonus depreciation (Section 168(k)) often gets lumped in with it, but they work differently, and in 2026 the difference matters a lot.

The percentage after the 2025 law change. Before 2025, bonus depreciation was phasing down. The 2025 law commonly known as the One Big Beautiful Bill Act changed that: for qualified property acquired and placed in service after January 19, 2025, bonus depreciation is 100% and permanent. Property acquired before January 20, 2025 but placed in service in 2026 is still under the old phase-down, at 20%. So when you acquired the asset (generally when you entered into the binding contract) can matter.

Can it create a loss? Yes. Unlike Section 179, bonus depreciation is not limited by business taxable income. It can create or increase a net operating loss. That can be useful, but NOLs come with their own limits, so a loss isn't automatically a win.

The elections. Section 179 is something you elect into, asset by asset, and you choose how much to expense. Bonus depreciation is the default. It applies automatically unless you elect out, and that election is made by class of property (for example, all 5-year property), not asset by asset. There's also a new option under the 2025 law: for property acquired after January 19, 2025, you can elect a reduced bonus rate in the first tax year ending after that date. These choices interact, and the best mix depends on your income this year, what you expect next year, and your state.

State conformity. This one bites people every year. Many states don't follow federal bonus depreciation, and some limit Section 179 to much lower amounts than the federal limit. A full federal write-off can leave you with an add-back on your state return and separate state depreciation schedules to track for years. Check your state's rules before you assume the state benefit matches the federal one.

Before you buy anything in December for tax reasons, run through this:

• Do you actually need the asset? A deduction saves only a portion of what you spend. Spending a dollar to save a fraction of a dollar is still spending.
• Can it be delivered, installed, and in use by December 31? Get it in writing.
• What's your projected active business income, including W-2 wages, for 2026?
• What's the realistic business-use percentage, and can you keep it above 50% going forward?
• If it's a vehicle, what's the GVWR? Check the label on the driver's side door jamb.
• When did you sign the purchase contract? It affects which bonus rate applies.
• How does your state treat Section 179 and bonus depreciation?
• Are your records ready? Invoice, proof of payment, delivery and in-service dates, and usage logs.

1. Based on my projected 2026 income, how much of a Section 179 deduction can I actually use this year?
2. Should I use Section 179, bonus depreciation, or a combination, and why?
3. Would I be better off spreading deductions into 2027 instead of front-loading them?
4. How will my state treat this purchase?
5. If this is a vehicle, which limits apply, and what records do I need to keep?
6. What happens if my business use drops in a future year?
7. Does financing the purchase change anything about timing or the deduction?

Section 179 can be a powerful planning tool when the timing, income, and usage tests are all met. It's not a magic eraser for your tax bill, and "write it all off" isn't how it works. Make the decision based on what your business needs and what the numbers actually show, so your December purchase doesn't turn into a problem you're explaining to an IRS examiner a few years from now.

Talk to your CPA before you buy, not after.

Dustin J. Heath, CPA

This article is for general informational purposes only and is not tax, legal, or accounting advice for your specific situation.

• 2026 Section 179 limit ($2,560,000), phase-out threshold ($4,090,000), and heavy-SUV limit ($32,000): IRS Rev. Proc. 2025-32, Section 4.24. https://www.irs.gov/pub/irs-drop/rp-25-32.pdf (also listed in IRS Publication 946, "What's New for 2026": https://www.irs.gov/pub/irs-pdf/p946.pdf)
• 2026 first-year Section 280F caps ($20,300 with bonus; $12,300 without), and the 100% / 20% bonus depreciation rates: IRS Rev. Proc. 2026-15. https://www.irs.gov/pub/irs-drop/rp-26-15.pdf
• Section 179 rules (taxable income limit, carryforward, SUV definition): 26 U.S.C. § 179. https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title26-section179