Accountable Plan Rules Every S Corporation Owner Needs

9 min read

You wrote the check personally. The client dinner, the flight, the printer for the home office, the mileage running between two job sites. It was a business expense, so you assumed it would land somewhere useful on a tax return.

For an owner who takes a W-2 from their own S corporation, it usually lands nowhere at all.

That is not a technicality. It is the current state of the law, and it changed in a way most business owners never heard about. The fix is a document most businesses do not have — an accountable plan. Filing taxes looks backward. This is one of the places where looking forward pays for itself.

Why unreimbursed business expenses stopped working

Before 2018, an employee who paid business costs out of pocket could claim them as a miscellaneous itemized deduction, subject to a floor of two percent of adjusted gross income. The Tax Cuts and Jobs Act suspended that category. Most people filed it away as a temporary change with a 2025 expiration date.

It is no longer temporary. In Notice 2026-10, the IRS states that section 70110 of the One Big Beautiful Bill Act “made permanent the disallowance for all miscellaneous itemized deductions that are subject to the two-percent of adjusted gross income floor under § 67, including unreimbursed employee travel expenses.”

A narrow list of taxpayers still files Form 2106 — reserve component members of the Armed Forces, fee-basis state and local officials, qualified performing artists, and eligible educators. The IRS confirms this short list in Topic no. 511, Business travel expenses. Business owners are not on it.

So an owner-employee of an S corporation now has exactly one path for out-of-pocket business costs.

• The company reimburses you under a written accountable plan, and the money reaches you tax free
• The company reimburses you without a qualifying plan, and the money becomes taxable wages
• The company does not reimburse you at all, and the deduction is simply gone

The third outcome is the most common one we see when a new client brings in a prior year return. This is the kind of gap that proactive tax planning is built to catch before it repeats for a fourth or fifth year.

The three tests that make a plan accountable

The governing rule is Treasury Regulation section 1.62-2. It sets three tests, and an arrangement has to clear all three. Miss one and every dollar paid under the arrangement is treated as coming from a nonaccountable plan.

Business connection

Under Regulation section 1.62-2(d), the arrangement must provide advances, allowances, or reimbursements “only for business expenses that are allowable as deductions” and “paid or incurred by the employee in connection with the performance of services as an employee of the employer.”

Two words in that sentence carry weight. Employee, and only. A plan that also reimburses personal costs is not a partially accountable plan. It fails.

Substantiation

The arrangement has to require each expense to be substantiated to the company within a reasonable period of time. Not tracked loosely. Not reconstructed in March. Substantiated, to the payor, per expense.

Returning amounts you did not spend

If the company advances you money and you spend less than the advance, the plan must require you to return the difference within a reasonable period. Publication 463 states the same three tests in plain language in its chapter on reimbursements, which is a useful page to hand to whoever runs your books.

How fast you have to move on substantiation

“Reasonable period of time” sounds like an invitation to argue. The regulation removes the argument by giving a safe harbor with hard numbers, and this is where most homemade plans fall apart.

Regulation section 1.62-2(g)(2)(i) treats the following as occurring within a reasonable period.

1. An advance made within 30 days of when the expense is paid or incurred
2. An expense substantiated to the company within 60 days after it is paid or incurred
3. An amount returned to the company within 120 days after the expense is paid or incurred

There is a second route. If the company sends employees a statement at least quarterly showing amounts paid that have not yet been substantiated, and asks for substantiation or return within 120 days of that statement, meeting that window also counts as reasonable.

Neither route survives a shoebox of receipts handed over at year end. The reimbursement side of an S corporation is a monthly discipline, and treating it as a filing-season task is the difference between a clean deduction and a payroll adjustment. Section 5 of Publication 15, Circular E is the employer-facing version of these rules and covers how the reimbursement is reported.

This is also the practical line between tax preparation and tax strategy, a distinction we walk through in tax planning versus tax preparation.

What records the IRS actually requires

Substantiation is not a single standard. It varies by expense type, and the requirements come from Regulation section 1.274-5.

For travel away from home, the regulation requires four elements for each expenditure — amount, time, place, and business purpose. Dates of departure and return. The city or locality. The business reason for the trip. Daily meal costs may be aggregated into reasonable categories rather than itemized meal by meal.

Receipts are a separate question from the four elements. Under Regulation section 1.274-5(c)(2)(iii), documentary evidence is required for any lodging expense while traveling away from home, and for any other expenditure of 75 dollars or more.

• Lodging needs a receipt regardless of the amount
• Everything else needs a receipt at 75 dollars and above
• Transportation charges are excused when documentary evidence is not readily available
• Vehicles require the amount of each expenditure plus business mileage as the measure of business use

That last item is why a vehicle log is not optional. Vehicles are listed property, and the regulation names mileage as the measure of business use. If you are weighing how the vehicle itself should be owned and paid for, our breakdown of car lease tax deductions covers the choice that comes before the reimbursement question.

Mileage rates and per diem shortcuts

Two shortcuts reduce the paperwork without weakening the plan, and one of them changed mid-year.

The 2026 business standard mileage rate is not a single number. Notice 2026-10 set it at 72.5 cents per mile effective January 1, 2026. Announcement 2026-11 then modified that notice, raising the business rate to 76 cents per mile for miles driven on or after July 1, 2026, citing fuel price increases. Both periods appear on the IRS standard mileage rates table, which is the page to check rather than relying on a figure you saw in January.

A reimbursement at the standard rate still requires the mileage log. The rate substitutes for proving the cost per mile, not for proving the trip.

Per diem works the same way for travel. Revenue Procedure 2019-48 allows a company to reimburse meals and incidental expenses, or lodging plus meals, at a flat daily rate instead of collecting receipts. Notice 2025-54 carries the current rates for travel on or after October 1, 2025 — 319 dollars per day for high-cost localities and 225 dollars for other locations in the continental United States, with 86 dollars and 74 dollars of those amounts treated as meals.

Per diem substantiates the amount only. The employee still has to substantiate time, place, and business purpose within a reasonable period. Expect a replacement notice each fall, so the rate table is worth re-checking annually rather than hard-coding into a policy.

Where the home office fits and what to do next

Here is where we will be more careful than most articles on this subject, because the honest answer is more useful than a confident one.

Section 280A of the code allows a home office deduction for a principal place of business, but it adds a condition that applies specifically to employees. The exclusive use must be “for the convenience of his employer.” Meanwhile Publication 587 is written for self-employed individuals and partners, and its own flowchart routes an employee to no deduction — because the employee-level deduction is the one that went away.

The reimbursement analysis is a different question from the deduction question, and it runs through the three tests above rather than through Publication 587. What we can tell you plainly is that the IRS has not published guidance applying accountable plan reimbursement specifically to an S corporation owner-employee’s home office. Practitioners rely on the regulation text. That is a defensible position, not a settled one, and it deserves a real conversation about your facts rather than a template. Our post on home office deductions for S corporations walks through the measurement side of that analysis.

The rest of the setup is straightforward and worth doing this quarter. Adopt the plan in writing before the reimbursements start. Set a submission cadence that lands inside 60 days. Reimburse from the business account, separately from payroll, so the entries are legible later. And confirm the wage side is right, because reimbursements sit on top of reasonable compensation rather than replacing it — the IRS lists the factors it weighs on its page covering S corporation compensation, and we cover the exposure in reasonable salary rules.

Talk to us before the next expense clears

An accountable plan is a short document that changes the tax treatment of money already moving through your business. Most owners we meet have been absorbing those costs personally for years without knowing the deduction went away permanently.

If you want a second opinion on how your reimbursements, salary, and entity structure fit together, we would be happy to take a look. Schedule a no-obligation evaluation and we will tell you what we find, including when the answer is that your current setup is already working.

Frequently asked questions

Q: Does an accountable plan have to be in writing

A: The regulation describes an arrangement that requires business connection, substantiation, and return of excess amounts. In practice those requirements are proved by a written plan and the records created under it, which is why a written document adopted before reimbursements begin is the standard approach.

Q: What happens if my plan fails one of the three tests

A: Regulation section 1.62-2(c)(5) states that amounts paid under a nonaccountable plan are included in the employee’s gross income, must be reported as wages on Form W-2, and are subject to withholding and employment taxes. A single failed test converts every dollar paid under the arrangement.

Q: Can I reimburse myself for expenses from a prior year

A: The safe harbor treats substantiation within 60 days of the expense as reasonable. Reimbursements for expenses that are years old sit well outside that window, and the deduction for those years is generally not recoverable through a current-year reimbursement.

Q: Do accountable plan reimbursements show up on my W-2

A: No. Regulation section 1.62-2(c)(4) states that amounts paid under an accountable plan are excluded from gross income, are not reported as wages on Form W-2, and are exempt from withholding and employment taxes.

Q: Can a sole proprietor use an accountable plan for themselves

A: The regulation applies to expenses incurred by an employee performing services as an employee. A sole proprietor is self-employed rather than an employee of the business, so the mechanism does not apply to the owner personally, though it does apply to their employees. Partners are treated as self-employed as well and use a different route.

Q: Which mileage rate applies to a trip in July 2026

A: The 76 cent rate. Announcement 2026-11 modified Notice 2026-10 and applies to business miles driven on or after July 1, 2026. Miles driven between January 1 and June 30, 2026 use the 72.5 cent rate.

Q: Is per diem safer than collecting receipts

A: It reduces the recordkeeping burden but does not eliminate it. Per diem substantiates the amount of the expense. The employee still has to substantiate the time, place, and business purpose of the travel within a reasonable period of time.