Fiscal Year End Meaning: Choosing Dates and Filing Deadlines

A fiscal year end is the last day of the 12-month accounting period your business uses for financial reporting and tax filing. It does not have to be December 31. The IRS defines a fiscal year as 12 consecutive months ending on the last day of any month other than December, while a calendar year always runs January 1 through December 31.¹ A business with a June 30 fiscal year end reports on the 12 months ending that date; a company with a September 30 fiscal year end reports on the 12 months ending then. The date you pick, or the one you’re stuck with, sets your tax deadlines and drives when your books get closed.

Who Can Choose a Non-Calendar Year

Whether you have a real choice depends on how your business is organized.

C-Corporations

C-Corps have the most flexibility. They can adopt any 12-month period ending on the last day of a month.¹ A C-Corp whose business cycle wraps up in early fall might close its books September 30 and never touch a calendar year.

S-Corporations

S-Corps default to the calendar year. The IRS treats December 31 as the “required taxable year” for an S-Corp.² To use anything else, you have to either prove a business purpose to the IRS or make a Section 444 election.

Partnerships and LLCs Taxed as Partnerships

Partnerships follow a tiered test. The partnership must adopt the taxable year of the partners who together own more than 50% of profits and capital. If no year hits that threshold, it uses the year shared by all principal partners (5% or more). If neither test works, it defaults to the calendar year.³ LLCs taxed as partnerships follow the same rules.

Sole Proprietors

The IRS requires a calendar year if you keep no books, have no established accounting period, or your current year doesn’t qualify as a fiscal year.⁴ In practice, almost all sole proprietors use December 31, because individual income tax runs on the calendar year and a mismatch rarely helps.

The Section 444 Election

S-Corps, partnerships, and personal service corporations that want a non-calendar year without going through the business-purpose approval can file a Section 444 election. The limit: the elected year can’t create a deferral period longer than three months.⁵ An S-Corp that would otherwise use December 31 could elect September 30 (three months of deferral) but not June 30 (six months). Electing entities also owe required deposits under Section 7519 to offset the deferral, which cancels much of the cash-flow benefit that made the election attractive in the first place.

Picking a Fiscal Year End

If you have the flexibility to choose, the useful concept is the “natural business year.” That’s the 12-month period that ends right after your peak activity, when inventory and receivables are at their lowest. Closing at the quiet point makes inventory counts easier, cleans up the revenue picture, and gives you a clearer read on how the year actually performed.

The IRS has a formal test for this: the 25-percent gross receipts test. Add the gross receipts for the last two months of your proposed year and divide by total receipts for the full 12 months. If that ratio is 25% or higher for each of the three most recent years, the IRS treats the proposed date as your natural business year.⁶ You need at least 47 months of gross receipts data to run the test, so brand-new companies can’t use it. If some other month-end produces a higher average than the one you’re requesting, your proposed year won’t qualify.

Common Fiscal Year End Dates

December 31 is still the most common choice overall, but several industries pick something else to match their operating rhythm.

Retail: Many large retailers end near January 31, after the holiday season and returns have settled. Target’s fiscal year ends the Saturday nearest January 31; Lowe’s ends the Friday nearest the end of January.
Technology: Apple closes on the last Saturday of September using a 52/53-week structure. Microsoft uses June 30.
Entertainment: Walt Disney ends on the Saturday closest to September 30.
Nonprofits and universities: Many run July 1 through June 30, matching program and academic cycles.
Federal government: The U.S. federal fiscal year runs October 1 through September 30. Federal “fiscal year 2026” means October 1, 2025 through September 30, 2026.⁷

The pattern is consistent. Businesses close the books when things are quietest, so they aren’t trying to reconcile the year while peak operations are still running.

The 52/53-Week Fiscal Year

A standard fiscal year always ends on the last calendar day of a month. A 52/53-week fiscal year ends on the same day of the week instead, such as the last Saturday in September or the Saturday nearest January 31.⁴ The trade-off is that the year alternates between 52 weeks (364 days) and 53 weeks (371 days), with the extra week appearing every five or six years to keep the year-end from drifting away from the target month.

Retailers and manufacturers favor this structure because every fiscal period lines up cleanly for comparison. Each quarter contains exactly 13 weeks, so you’re always comparing the same number of Saturdays and the same number of each weekday across periods. The National Retail Federation publishes a standardized 4-5-4 calendar that splits each quarter into months of four, five, and four weeks.⁸ Without that structure, one calendar month might have four Saturdays this year and five next year, distorting same-store sales comparisons.

Filing Deadlines Tied to Your Fiscal Year End

Your fiscal year end sets your tax return due date, and the timing differs by entity.

C-Corporations (Form 1120): due on the 15th day of the 4th month after the fiscal year ends. A December 31 FYE files by April 15; a June 30 FYE files by October 15.⁹
S-Corporations (Form 1120-S): due on the 15th day of the 3rd month after the fiscal year ends. Schedule K-1s must reach shareholders by the same date.⁹
Partnerships (Form 1065): due on the 15th day of the 3rd month after the fiscal year ends, with K-1s to partners by the same deadline.⁹

S-Corps and partnerships file a full month earlier than C-Corps because their K-1 information has to flow through to individual owners in time for those owners to file their own returns.

Form 7004 grants an automatic six-month extension for most business entities.¹⁰ “Automatic” means the IRS doesn’t weigh your reasons; file the form on time and you get the extension. It’s an extension to file, not an extension to pay. Estimated tax is still due on the original deadline, and any unpaid balance starts accruing interest and penalties from that date.

Changing Your Fiscal Year End

Once you’ve filed a return using a particular year-end, you can’t switch without IRS approval. The request goes on Form 1128, which has an automatic approval track and a ruling request track for situations that don’t qualify for automatic approval.¹¹

If your situation qualifies for automatic approval under an IRS revenue procedure, you file Form 1128 by the due date (including extensions) of the return for the short period created by the change. Otherwise, you file a ruling request by the due date of the return for the first year under the new period, and the IRS evaluates whether you have a valid business purpose. Applications filed more than 90 days late are presumed to harm the government’s interests and are approved only in unusual circumstances.

One thing to watch: don’t file a return on the new year-end before the IRS actually approves the change. Doing that creates problems that are much harder to unwind than waiting for the approval letter.

Short Tax Years

Changing your fiscal year creates a short tax year covering fewer than 12 months. Moving from December 31 to September 30 would produce a short-period return for January 1 through September 30.¹² Short years also appear when a business forms or dissolves mid-year.

The tax on a short year isn’t calculated by simply reporting the partial-year income at ordinary rates. The IRS requires annualization: multiply the short-period income by 12, divide by the number of months in the short period, compute tax on the annualized figure, and then take a proportionate share as the actual tax.¹² The rule stops businesses from crowding deductions into a short period to knock themselves into a lower bracket.

Penalties for Missing the Deadline

The IRS charges separate penalties for filing late and paying late, and both can run at the same time.

The failure-to-file penalty is 5% of unpaid tax per month or partial month the return is late, capping at 25%. Returns more than 60 days late carry a minimum penalty of $525 for returns due after December 31, 2025. S-Corp and partnership returns work differently: $255 per shareholder or partner, per month, for up to 12 months.¹³ A ten-person partnership filing six months late would owe $15,300 in penalties on an informational return where the entity itself owes no tax.

The failure-to-pay penalty is 0.5% of the unpaid tax per month, also capping at 25%.¹⁴ If you filed on time and set up a payment plan, the rate drops to 0.25% per month. If the IRS issues a notice of intent to levy and you still don’t pay within 10 days, the rate rises to 1% per month. Interest accrues on top of all of it.

Against those numbers, filing Form 7004 is one of the cheaper moves in tax planning. It takes minutes and buys six months.

1
Office of the Law Revision Counsel. 26 USC 441 – Period for Computation of Taxable Income
2
eCFR. 26 CFR 1.1378-1 – Taxable Year of S Corporation
3
Office of the Law Revision Counsel. 26 USC 706 – Taxable Years of Partner and Partnership
4
Internal Revenue Service. Tax Years
5
United States Code. 26 USC 444 – Election of Taxable Year Other Than Required Taxable Year
6
Internal Revenue Service. Revenue Procedure 2002-39 – Procedures for Establishing a Business Purpose for an Annual Accounting Period
7
USAGov. The Federal Budget Process
8
NRF. 4-5-4 Calendar
9
Internal Revenue Service. Publication 509 (2026), Tax Calendars
10
Internal Revenue Service. Instructions for Form 7004 (12/2025)
11
Internal Revenue Service. Instructions for Form 1128
12
Office of the Law Revision Counsel. 26 USC 443 – Returns for a Period of Less Than 12 Months
13
Internal Revenue Service. Failure to File Penalty
14
Internal Revenue Service. Failure to Pay Penalty