Every year, thousands of business owners pay for mileage, a home office, a phone plan, and professional dues out of their own pockets and assume it all shakes out on their tax return. For many of them it does not, and after 2025 it never will. The One Big Beautiful Bill Act made the elimination of miscellaneous itemized deductions permanent, which means an employee, including an S-corporation owner on payroll, gets no personal deduction for business expenses the company does not reimburse.
The fix is old and cheap: an accountable plan. Set up correctly, it lets the company deduct the expense and pay you back tax-free, with no W-2 income and no payroll tax. Set up carelessly, the same reimbursements become taxable wages. With fourth-quarter planning underway and new federal per diem rates taking effect October 1, now is the time to put one in place.
Why the Lost Deduction Makes Reimbursement Essential
Before 2018, employees could deduct unreimbursed business expenses above 2 percent of adjusted gross income. The 2017 tax law suspended that deduction through 2025, and the 2025 law ended it for good. Sole proprietors are unaffected, since their expenses go straight onto Schedule C. The people hurt most are owners who converted to an S corporation: a more-than-2-percent shareholder who works in the business is an employee, so the home office they used to claim on their own return has nowhere to go.
Three Ways to Handle $12,000 of Owner Business Expenses
- Owner pays, company never reimburses: no deduction for anyone. The $12,000 is spent with after-tax dollars.
- Flat monthly allowance with no receipts: the company deducts $12,000 as wages but owes $918 in employer FICA; the owner pays income tax on $12,000 plus another $918 in employee FICA.
- Accountable plan reimbursement: the company deducts $12,000, the owner receives $12,000 tax-free, and nothing appears on the W-2.
The Three Rules an Accountable Plan Must Meet
The Treasury regulations set out three requirements. Miss any one and the payments are treated as coming from a nonaccountable plan, meaning they are wages subject to income tax withholding, Social Security, Medicare, and federal unemployment tax.
- Business connection. The expense must be one the employee incurred while performing services for the employer and would be deductible as a business expense.
- Adequate substantiation. The employee must document the amount, date, place, and business purpose within a reasonable period. For travel, meals, and vehicles, the stricter Section 274 recordkeeping rules apply.
- Return of excess. Any advance or allowance beyond substantiated expenses must be returned within a reasonable period.
What “Reasonable Period” Means in Practice
The regulations provide two safe harbors, and your policy should adopt one of them explicitly.
| Safe Harbor | Advances | Substantiation | Return of Excess |
|---|---|---|---|
| Fixed date method | No more than 30 days before the expense | Within 60 days after the expense is paid or incurred | Within 120 days after the expense is paid or incurred |
| Periodic statement method | Reasonably calculated not to exceed expected expenses | Employer sends statements at least quarterly listing unsubstantiated amounts | Within 120 days after the statement is provided |
The regulations do not demand a formal plan document, but an unwritten plan is almost impossible to prove on audit. Adopt a written policy by board resolution and follow it for owners exactly as you do for staff.
What an Accountable Plan Can Reimburse
Vehicle Use
Reimburse business miles at the IRS standard mileage rate, 72.5 cents per mile for 2026, backed by a contemporaneous log showing date, destination, purpose, and miles. An owner who drives 6,000 business miles receives $4,350 tax-free. The classic failure is the flat $600-a-month car allowance paid regardless of miles driven: that is wages, every dollar. Employers wanting a fixed payment should look at a fixed and variable rate (FAVR) arrangement, which has its own rules.
Travel and Per Diem
Lodging and meals can be reimbursed at actual cost with receipts, or at federal per diem rates, which deem the amount substantiated as long as time, place, and business purpose are documented. The rates reset every October 1 with the federal fiscal year, so update your policy table now. Anything paid above the federal rate and not returned is taxable to the employee.
The Home Office
An S-corporation owner who uses part of the home regularly and exclusively for the business, for the convenience of the employer, can be reimbursed for the business-use share of rent or mortgage interest, utilities, insurance, and repairs. Submit the calculation with supporting bills, typically quarterly. This is separate from, and does not conflict with, renting the whole home to your company for meetings under the Augusta Rule.
Phones, Internet, and Professional Costs
- Cell phones and internet: the business-use portion of a personal plan, supported by bills.
- Licensing and dues: professional licenses, association memberships, and certifications.
- Continuing education: courses, conferences, and related travel that maintain or improve skills used in the job.
- Supplies and equipment: business items bought personally, with receipts.
Medical Practices Have More at Stake
Employed physicians, nurse practitioners, and physician assistants routinely spend thousands a year on CME, state license renewals, DEA registration, board certification fees, and conference travel. Since none of it is deductible on their personal returns, a practice that reimburses through an accountable plan delivers far more value per dollar than one that adds a CME stipend to the paycheck. It is also a recruiting point: a $5,000 accountable CME allowance is worth noticeably more than $5,000 of taxable salary. Build the policy into provider employment agreements, and make sure it squares with the compensation formulas our medical practice finance team models for partners and associates.
Mistakes That Turn Reimbursements Into Wages
- Reimbursing owners without paperwork because “it is my company.” The IRS looks hardest at shareholder-employees.
- Paying personal expenses directly from the business account and sorting it out at year end. That is a shareholder distribution or wages, not a reimbursement.
- Letting excess advances sit past the 120-day window instead of recovering or reclassifying them.
- Catch-up reimbursements in December for expenses from January, which fall well outside the safe harbor timelines.
- Setting a low salary and a large “expense” payment to dodge payroll tax, which invites a reasonable compensation challenge.
Clean reimbursements depend on clean records: expense reports that route through accounts payable, post to the right accounts in your bookkeeping, and stay out of payroll entirely.
The Bottom Line
With the employee business expense deduction permanently gone, every dollar an owner or employee spends for the business is either reimbursed correctly or lost. An accountable plan costs almost nothing to adopt: a written policy, a mileage log, a quarterly home office submission, and a habit of returning excess advances. In exchange, the business keeps its deduction and the people doing the work stop subsidizing it with after-tax income.
Want an accountable plan in place before year end? Schedule a free consultation and our tax strategy and CFO advisory teams will draft the policy, set up the reimbursement workflow, and review how your 2026 expenses have been handled so far.
