S Corp Accountable Plan: How to Reimburse Yourself for Home Office and Mileage

An accountable plan for an S corp solves a problem the S election creates. As a sole proprietor you deducted the home office and the car on Schedule C. As an S corporation owner you are an employee, and employees cannot deduct those costs at all. The fix is to have the corporation reimburse you under an arrangement that meets the accountable plan rules, so the corporation gets the deduction and you get the cash without it touching your W-2. This guide covers the three tests, the safe harbors, what an owner can be reimbursed for, the records, and what happens when a plan fails. The glossary entry at accountable plan has the short definition.

Why an S corp owner needs an accountable plan at all

Since the 2017 tax law, no miscellaneous itemized deduction is allowed for any tax year beginning after December 31, 2017, and P.L. 119-21 made that permanent by striking the 2026 end date (IRC 67(h), as redesignated). Unreimbursed employee business expenses are in that category, so an owner-employee who pays for a home office, mileage or a phone out of pocket gets nothing for it; Publication 463 says the same about an expense you could have claimed from your employer but did not (Publication 463). Reimbursement moves the deduction to the corporation, and the accountable plan rules in Treas. Reg. 1.62-2 decide whether the reimbursement is tax-free to you or just more wages.

The three tests in Treas. Reg. 1.62-2

An arrangement is an accountable plan if it meets paragraphs (d), (e) and (f) of the regulation; miss any one and every payment under it is treated as paid under a nonaccountable plan (Treas. Reg. 1.62-2(c)(2) and (3)). Publication 15 puts the same three rules to employers (Publication 15, section 5).

1. Business connection. The plan reimburses only business expenses that would be deductible under the Code and that the employee paid “in connection with the performance of services as an employee of the employer.” A reimbursement combined with wages in one payment must be separately identified, and an amount paid regardless of whether the employee incurs expenses is not a reimbursement (Treas. Reg. 1.62-2(d)(1) and (d)(3)).
2. Substantiation. Each expense must be substantiated to the corporation within a reasonable period. For car use and travel, that means the elements section 274(d) requires: amount, time, place or use, and business purpose (Treas. Reg. 1.62-2(e); IRC 274(d)). When the corporation pays the standard mileage rate, the amount is deemed substantiated and the owner still documents the time, place and purpose of each trip (Rev. Proc. 2019-46, section 7).
3. Return of excess. Any amount paid above the substantiated expenses must be returned within a reasonable period. An advance qualifies only if it is reasonably calculated not to exceed the anticipated expenses and is made within a reasonable period of when they are paid (Treas. Reg. 1.62-2(f)).

The 30, 60 and 120 days are a safe harbor, not deadlines

The regulation says a reasonable period “will depend on the facts and circumstances,” then offers two safe harbors (Treas. Reg. 1.62-2(g)). Under the fixed date method, an advance made within 30 days of the expense, substantiation within 60 days after it, and a return of excess within 120 days after it are each treated as within a reasonable period. Under the periodic statement method, the corporation sends a statement at least quarterly listing any unsubstantiated amounts and asking for substantiation or repayment within 120 days of the statement, and anything done inside that window counts. The safe harbors are lost for any year in which the payor has a plan or practice of paying more than the substantiated expenses to avoid withholding (Treas. Reg. 1.62-2(g)(3)). For an owner-employee the practical routine is a monthly expense report with the log and receipts attached, paid in the next payroll.

What an S corporation owner can be reimbursed for

Home office. The business connection test means the expense has to be one the Code would allow, and for a home that is section 280A(c)(1): part of the home used exclusively and regularly as the principal place of business, which includes administrative or management work when there is no other fixed location for it, or as a place to meet clients, or a separate structure. The section adds one condition for employees: the exclusive use must be “for the convenience of his employer” (IRC 280A(c)(1)). A corporation that provides no other office and requires the owner to work from home should say so in the plan. The IRS flowchart in Publication 587 sends an employee straight to “no deduction” on their own return (Publication 587), which is why the reimbursement route is the only one open to an S corporation owner.

Mileage. Two rates apply in 2026: 72.5 cents per business mile from January 1 to June 30 under Notice 2026-10, and 76 cents per mile on or after July 1 under Announcement 2026-11, which the IRS issued because of fuel prices (IRS standard mileage rates page). Driving between home and the regular place of work is commuting, which Publication 463 says cannot be deducted “no matter how far your home is from your regular place of work”; if the home office is the principal place of business, trips from it to clients are business trips.

Phone. A personal phone used partly for the business is reimbursed at the business share, with the bill and the basis for the percentage on file. A phone the corporation itself provides “primarily for noncompensatory business reasons” is a different rule, a working condition fringe under Publication 15-B, and needs no reimbursement at all.

A year of reimbursements (an illustration)

Records and how to run it through payroll

The corporation adopts the plan, the owner files an expense report each month with the mileage log, the home office computation and receipts, and the corporation pays the reimbursement as an item separate from wages, since the regulation requires a combined payment to identify the reimbursement amount. Paid through payroll as a non-taxable reimbursement line, it stays off the W-2 and out of the 941; Managed Payroll (from $25 per employee per month) handles it as a standing pay item. Keep the reports with the corporation's records for that year, because the deduction on Form 1120-S rests on them.

What happens under a nonaccountable plan

Amounts paid under a nonaccountable plan “are included in the employee's gross income, must be reported as wages or other compensation on the employee's Form W-2, and are subject to withholding and payment of employment taxes” (Treas. Reg. 1.62-2(c)(5)). The same result follows when an accountable plan is in place but the owner does not substantiate in time or does not return an excess: the unsubstantiated part becomes wages no later than the first payroll period after the reasonable period ends (Treas. Reg. 1.62-2(h)(2)(i)). And because the employee-side deduction no longer exists, wages are the end of the story: Publication 463 says an arrangement that repays business expenses by reducing the amount reported as wages is a nonaccountable plan, and that an employee cannot convert a nonaccountable plan by voluntarily accounting for expenses. The health insurance side of owner benefits works through the W-2 rather than around it; see how S corp owners deduct health insurance.

Sources: 26 CFR 1.62-2, reimbursements and other expense allowance arrangements; 26 U.S.C. 62(a)(2)(A) and (c), adjusted gross income defined; reimbursement arrangements; 26 U.S.C. 67, 2-percent floor on miscellaneous itemized deductions (subsection (h)); 26 U.S.C. 280A(c)(1), business use of a home; 26 U.S.C. 274(d) and (n), substantiation; 50% limit on meals; IRS, Publication 15 (2026), Employer’s Tax Guide, section 5; IRS, Publication 463 (2025), Travel, Gift, and Car Expenses; IRS, Publication 587 (2025), Business Use of Your Home; IRS, Publication 15-B (2026), Employer’s Tax Guide to Fringe Benefits; IRS, Notice 2026-10, 2026 standard mileage rates; IRS, Announcement 2026-11, Internal Revenue Bulletin 2026-29 (revised rates from July 1, 2026); IRS, Standard mileage rates (reviewed July 28, 2026); IRS, Rev. Proc. 2019-46, business standard mileage rate rules. Figures and rules checked against these sources on September 26, 2026. This is general information, not tax advice for your situation. Tax services are provided by licensed tax professionals under a separate engagement agreement. BEG does not provide tax advice.