In the calendar year that most people and small businesses use, Q4 is October 1 through December 31. On a fiscal year, Q4 is whatever three months close out that particular 12-month cycle, so the dates move with the start month a business has chosen. The U.S. federal government, for instance, runs its Q4 from July 1 through September 30. Same idea across all of them: Q4 is the final stretch of the reporting year, when books close, taxes come due, and next year’s budget gets locked in.
Calendar Year Q4: October Through December
The calendar year runs January 1 through December 31, so its fourth quarter is October, November, and December. This is the default for individuals, sole proprietors, and most small businesses that haven’t elected a different reporting period. When someone says “Q4” without context, this is almost always what they mean. The IRS organizes its own tax calendar the same way, listing October, November, and December as the fourth quarter’s months.1Internal Revenue Service. Fourth Quarter – Tax Calendar
Fiscal Year Q4 Depends on When the Year Starts
A fiscal year is any 12 consecutive months a business adopts for accounting and tax purposes. For IRS tax purposes, a fiscal year ends on the last day of any month other than December, since a December 31 close is just a calendar year.2Internal Revenue Service. Publication 538, Accounting Periods and Methods Wherever the year starts, Q4 is the final three months of that cycle.
A few common examples show how far the dates can move:
- February 1 start (many retailers): Q4 is November 1 through January 31. Walmart and Target use this cycle so the full holiday selling season lands inside a single fiscal year rather than getting split across two.
- July 1 start (many nonprofits and universities): Q4 is April 1 through June 30, which aligns reporting with the school year or grant funding cycles.
- October 1 start (federal government, and some federal contractors): Q4 is July 1 through September 30.
The flexibility is deliberate. Management picks a fiscal year-end that falls at a natural low point in activity, so the accounting team isn’t closing the books during the busiest weeks of the year. A retailer that ended on December 31 would be reconciling its biggest month and preparing year-end statements at the same time; ending on January 31 gives the finance team room to work after the holiday rush.
The Federal Government’s Q4: July Through September
The U.S. federal government’s fiscal year begins October 1 and ends September 30.3USAGov. The Federal Budget Process That puts its Q4 from July 1 through September 30, out of phase with the calendar Q4 most people picture.
The timing produces a well-documented spending surge. Agencies with unspent appropriations face pressure to obligate the remaining money before September 30, because unspent funds generally return to the Treasury. Research has found that roughly 16 percent of annual executive branch contract spending happens in September alone, nearly double what an even distribution would predict.4Mercatus Center. Curbing Wasteful Year-End Federal Government Spending: Reforming “Use It or Lose It” Rules If you sell to the federal government, that summer window is when contract activity peaks.
Tax Deadlines That Follow the End of Q4
The close of calendar Q4 sets off a cluster of federal tax deadlines in January and February. If you’re on a calendar year, these are the ones to keep on the radar.
The Fourth Estimated Tax Payment
Individuals who expect to owe $1,000 or more in federal tax after withholding and refundable credits generally have to make quarterly estimated payments using Form 1040-ES. Corporations with an expected liability of $500 or more use Form 1120-W.5Internal Revenue Service. Estimated Taxes
One quirk catches people off guard: the IRS estimated-tax “quarters” are not four equal three-month periods. The fourth payment period actually covers September 1 through December 31, a full four months, and the payment is due January 15 of the following year.6Internal Revenue Service. When to Pay Estimated Tax You can skip that January 15 payment entirely if you file your complete return and pay the balance due by February 1.7Internal Revenue Service. Form 1040-ES (2026)
Payroll Tax Filings
Employers file Form 941, the quarterly return covering withheld income tax, Social Security, and Medicare, by the last day of the month after each quarter closes. For Q4, that’s January 31. If every employment tax deposit for the quarter went in on time, you get an extra 10 calendar days to file.8Internal Revenue Service. Employment Tax Due Dates
The annual federal unemployment tax return, Form 940, comes due right after Q4 as well. For the 2025 tax year the deadline is February 2, 2026, with the same 10-day extension available if all FUTA deposits were on time. If your fourth-quarter FUTA liability plus any undeposited amounts from earlier quarters is over $500, the full amount has to be deposited by that same February date.9Internal Revenue Service. Instructions for Form 940 (2025)
1099s and Other Information Returns
Businesses that paid independent contractors, distributed retirement funds, or made other reportable payments during the year owe information returns after Q4 closes. Form 1099-NEC for nonemployee compensation must be furnished to recipients and filed with the IRS by January 31. Most other 1099 variants, including 1099-MISC, 1099-INT, and 1099-R, go to recipients by January 31 too, but the IRS filing deadline for those forms is February 28, or March 31 if you file electronically.10Internal Revenue Service. Publication 1099, General Instructions for Certain Information Returns (2026)
Public Companies Don’t File a Q4 10-Q
Publicly traded companies skip the standalone Q4 quarterly report. Fourth-quarter results get folded into the annual Form 10-K, which carries audited financial statements for the full fiscal year.11Legal Information Institute. Form 10-K The filing window depends on company size:
- Large accelerated filers (public float of $700 million or more): 60 days after fiscal year-end
- Accelerated filers (public float of $75 million to $700 million): 75 days after fiscal year-end
- Non-accelerated filers (below $75 million): 90 days after fiscal year-end
For Q1 through Q3, companies file the shorter, unaudited Form 10-Q, which is due 40 days after quarter-end for large accelerated and accelerated filers and 45 days for non-accelerated filers. The 10-K replaces the Q4 10-Q, and it takes longer because auditors are reviewing the whole year.
Q4 earnings calls usually happen within a few weeks of quarter-end, well before the 10-K itself lands. Alphabet held its Q4 2025 earnings call on February 4, 2026, just over a month after the December 31 close. Those calls tend to move stock prices more than the eventual filing because they carry forward-looking management commentary that the 10-K does not.
Q4 as the Year-End Close
For consumer-facing businesses on a calendar year, October through December often decides whether the full year lands in profit or loss. Holiday spending drives the bulk of retail sales, and many companies count on Q4 to cross from red to black.
Internally, Q4 is also when most organizations finalize next year’s operating budget. Capital expenditure requests, headcount plans, and departmental allocations get settled during this window, and physical inventory counts near fiscal year-end reconcile what’s on the shelves with what’s in the books, feeding the numbers that show up in the annual report. On a non-calendar fiscal year, the same pressures just move: a company ending June 30 runs its own budget finalization and inventory work during April through June. The calendar dates change; the intensity of year-end close doesn’t.