Here's a scenario we see all the time. A client trades in their work truck for a new one, and we don’t hear about it until a new loan payment shows up on their books. By then, the deal is signed, the old truck is gone, and most of the decisions that affect their taxes have already been made.
You needed the truck, so you bought it. But every big purchase has a tax side and a cash flow side, and both are much easier to plan before you sign than to sort out afterward.
That’s why we always ask our clients to call us before they sign. At Patrick Accounting, a small business accounting firm in Memphis, our mission is to give business owners across the country the opportunity to thrive by simplifying their financial complexities. A big purchase is one of the best places to do that, as long as we hear about it early.
This article covers the five problems we see most when owners buy first and tell their accountant later. You’ll also learn what to bring us before your next purchase to help you avoid them.
The Short Version:
When your accountant hears about a big purchase after you sign, five problems tend to show up: ownership gets locked in, deductions get missed or overestimated, a big deduction leaves you short on cash, your books show the wrong profit, or the purchase never pays for itself. A short conversation before you sign can help you avoid them. All you need to bring is the quote, the payment terms, any trade-in details, and how you'll use it.
Locking In the Wrong Ownership Structure for a Big Purchase
With a big purchase, you make most ownership decisions the day you sign. Should the vehicle be titled in your name or the business's? Should you lease or buy? Should a building belong to your operating company or to a separate entity?
These choices are easy to make before you sign and much harder to change afterward. Undoing them can mean extra paperwork, legal fees, and sometimes taxes.
Real estate is the biggest example. If your business is buying the building it operates in, owning it through the operating company isn't your only option. Some owners hold the building in a separate LLC and have the business pay rent to it, which can help separate the property from some of the operating business's liabilities and give you more flexibility if you ever sell.
Whether that's right for you depends on your financing, who owns the business, your taxes, and your attorney's advice. So, the time to talk it through with your accountant and attorney is before closing.
Missing or Overestimating Tax Deductions on a Big Purchase
When we don’t know the details of a purchase, an asset can go undepreciated because nobody told us it existed. Or an owner counts on a big write-off that the purchase doesn't actually qualify for.
Vehicles are the classic example. You may have heard that a vehicle over 6,000 pounds can be written off in full. Sometimes that's true, but weight alone doesn't make the whole purchase deductible. Here's what decides it:
- The manufacturer's gross vehicle weight rating, usually printed on a sticker inside the driver's door, along with the type of vehicle
- How much you use it for business, since a vehicle generally has to be used more than 50% for business to qualify for Section 179 or bonus depreciation
- Whether you keep records that back up that business use
Even when a vehicle qualifies for a full write-off, that generally means the business-use share of its cost, not the personal-use share. Different limits can also apply depending on the vehicle and which deduction you use. And if business use drops to 50% or less during the recovery period, you may have to report some of those earlier deductions as income.
Timing is the other part of the equation. For a calendar-year business, equipment generally has to be ready and available for business use by December 31 to start depreciating that year. Ordering it or putting down a deposit isn't enough if it won't be ready until January.
That said, only buy before year-end if the purchase makes sense on its own. A $10,000 deduction lowers your taxes by only a portion of that $10,000, depending on your tax rate, so you’re still spending more than you save.
Running Short on Cash After a Big Tax Deduction
How you pay for a purchase affects your cash flow and your taxes, and sometimes the two pull in opposite directions.
Paying cash means no interest, but if it drains your reserves, one slow month can turn into a crisis.
Financing keeps more cash in the bank, but you’ll pay interest. Many owners are also surprised to learn you can often deduct qualifying equipment in full the year you start using it, even though you’ll pay for it for years.
That full write-off is more common now than it used to be. The One Big Beautiful Bill Act restored 100% bonus depreciation for qualifying property acquired and placed in service after January 19, 2025, and raised the Section 179 limits. Federal tax rules determine the federal deductions, and your state may treat them differently.
Say you finance a $60,000 truck over five years. It qualifies for a full write-off, you use it only for business, and you deduct the full $60,000 this year. That lowers this year’s taxable income, which feels great. But for the rest of the loan, you’re still making payments with no depreciation deduction left on that purchase price. The principal portion isn’t deductible, though the business-use interest may be. You could have taxable profit while some of your cash is going to the bank to pay down that loan.
With a true lease, you generally deduct the business-use portion of each payment as you go, though some leases are treated as purchases for tax purposes, so we'll want to review the terms.
Taking the biggest deduction right now isn’t always the best move. If you expect to be in a higher tax bracket later, spreading deductions over time may work better. We can compare the options before you decide.
Recording a Big Purchase Wrong on Your Books
When a purchase shows up on your books as an unexpected payment, the payment alone doesn’t tell us what happened. We need the details to record it correctly. A common example is the whole loan payment being recorded as an expense. The principal part of the payment pays down the loan. It isn’t an expense. The interest is generally an expense. Mixing the two makes your profit look lower than it really is, and it’s hard to make good decisions from numbers that are off.
Trade-ins cause trouble too. If the dealer gives you more for your old truck than its remaining tax basis (usually its cost minus depreciation), the difference can be a taxable gain, even though you never got a check. If you used the truck only for business and already deducted its full cost, the trade-in value generally counts as taxable gain.
The same goes for personal purchases made with company money, or company funds invested in another business. If we don’t know what a payment was for, we can’t record it correctly, and untangling it later takes time and money.
Buying Equipment That Never Pays for Itself
When you buy new equipment, you’re usually expecting it to bring in more revenue, save time, or let you offer a new service. But if nobody runs the numbers before you buy, it’s easy to end up paying for a machine that never earns back what it cost, especially once you add supplies, maintenance, and the staff time it takes to run it.
The solution is to do that math before you sign. One of our longtime clients, an optometrist, handles this really well. Whenever he's thinking about new equipment, he loops us in first, and we work through the questions together:
- What he'll charge for the service and how many patients he expects to see with it
- What supplies, maintenance, staffing, and other ongoing costs come with it
- How depreciation works on it and what it does to his taxes
From there, we can estimate how long the machine will take to pay for itself. This information helps him make better decisions.
What Should You Tell Your Accountant Before a Big Purchase?
Reducing the risk of all five problems starts with one conversation, and you don't need to know the tax rules to have it. For a vehicle, here's what we'll ask and why:
|
What we'll ask |
Why we ask |
|
What are you planning to buy, and what will it cost? |
Sets the value we record and depreciate |
|
Are you trading something in? |
The old vehicle comes off your books, and the trade can create a taxable gain or a loss |
|
What’s the old vehicle’s remaining tax basis? |
Along with the trade-in value and business-use history, helps us calculate any taxable gain or deductible business loss |
|
Does the quoted price include sales tax? |
Sales tax generally becomes part of the vehicle's cost |
|
What type of vehicle is it, and what’s its weight rating? |
Helps us determine which depreciation rules and limits apply |
|
How much will you use it personally? |
Affects the deduction and may need to be reported as taxable pay |
For equipment, software, furniture, and building improvements, we’ll start with the same basics: what you’re considering, what it costs, how you’ll pay for it, and how you’ll use it.
What Your Next Big Purchase Could Look Like
For many business owners, the accountant hears about a big purchase at tax time, after the ownership, financing, and purchase decisions have already been made.
Now you understand the five problems that come with that timing, and how one conversation before you sign can help you avoid them.
Picture your next big purchase going differently. You call your accountant before you sign, you run the numbers together, and you buy with a clear picture of what it means for your cash and your taxes. That’s how we work with clients at Patrick Accounting, and it’s our favorite part of the job.
If your accountant usually only hears from you at tax time, that timing can cost you far more than a single purchase. “The Expensive Truth About Only Using Your Accountant at Tax Time” shows what it could cost you for the rest of the year.
Frequently Asked Questions About Business Purchases and Taxes
Can I write off the full cost of a vehicle over 6,000 pounds?
Sometimes, but weight alone doesn’t qualify you for a full write-off. It depends on the manufacturer’s gross vehicle weight rating, the vehicle type, how much you use it for business, and the applicable deduction rules. You generally need more than 50% business use to qualify for Section 179 or bonus depreciation, and you'll need records to support it. Even then, only the business-use portion of the cost qualifies, not the personal-use portion. Check with your accountant before counting on a full write-off.
Is it better to pay cash or finance a big business purchase?
It depends on your cash reserves and your tax situation. Paying cash avoids interest, but it can leave you short if business slows down. Financing protects your cash, but if you deduct the full cost up front, you’ll keep making loan payments after the deduction is used up. Your accountant can compare both before you decide.
Does a used purchase qualify for bonus depreciation?
In many cases, yes, as long as it’s new to your business and meets the other rules. For example, you generally can’t buy it from a related party, like a family member or another company you own. Have your accountant check before you count on the deduction.
When should I call my accountant about a big purchase?
As soon as you’re seriously considering it, and before you sign anything. A quote or proposed agreement is enough to get started.
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