Every company in our 90-day compliance window has the same statutory obligation and the same nine-month filing clock, yet almost all of them land on a single date. Right now, 39 tracked companies have accounts due between today and mid-December — and 28 of them, nearly three in four, are due on exactly the same day: 30 September. The other eleven are scattered across six dates in late September, and four of those spill weeks or months past the pile-up entirely. That split isn’t randomness — it’s a direct, checkable consequence of when each company’s financial year happens to end.
Why 30 September is where everyone lands
Companies House gives a private company nine months from its accounting reference date — the last day of its financial year — to file. Add nine months to 31 December and you land on 30 September — and sure enough, 22 of the 28 companies due that day, 79%, closed their last set of accounts on 31 December. A calendar-year financial year is the default most incorporations start with and the one most never change, so the filing deadline inherits that same default nine months later. The cluster is 22 unrelated companies making the same unremarkable choice years apart, all converging on one date because the arithmetic is identical.
The remaining six September filers — EFG Food & Tech Holdings (26th), A.J.Worldwide Services (27th), Upstream Mobile Commerce and 4Ds (Holdings), both West Yorkshire firms (28th), Stannp and Passenger Clothing (29th) — sit close to the cluster because their own year-ends fall a few days either side of 31 December, nothing more unusual than that.
The four that actually escape it
Four companies break the pattern by a much wider margin: Greenhalgh’s Craft Bakery (Greater Manchester, £26.2m, county rank #17), due 30 October; AKN Build (Leicestershire, £24.3m, rank #8), due 23 November; Reays Coaches (Cumbria, £6.3m, rank #4), due 26 November; and Techjoint (Surrey, £19.3m, rank #15), due 30 November. Together they carry £76m in turnover — a rounding error next to the cluster’s £1.2bn, but a genuinely different filing rhythm.
The mechanism checks out the same way it did for the cluster, just with different source dates. Greenhalgh’s last accounts were made up to 30 January 2025; nine months later is 30 October 2026 — exactly the date on file. Techjoint’s last accounts closed 28 February 2025, and end-of-month periods roll forward to the end of the month nine cycles later, landing on 30 November. AKN Build’s last accounts also closed 28 February 2025, yet its next filing is due 23 November — a week earlier than the month-end rule predicts, pointing to a shortened accounting reference period somewhere in its filing history rather than a plain nine-month roll. Reays Coaches closed 27 February 2025 and is due 26 November, a day short of the plain count for the same reason. Neither gap is worth chasing down as an error; it’s a reminder that “nine months from year-end” is the rule of thumb, not the whole rulebook, and a business that has ever shortened or extended a reporting period keeps filing slightly off the pattern its peers follow.
What the split is actually worth knowing
None of this changes what any company owes or when — Companies House enforces the same deadline either way. What it changes is how useful “days until due” is as a monitoring signal on its own. For 28 companies, that countdown converges on one date and says nothing about which is worth a closer look before it lands. For the four outliers, the countdown does real work: each is the only filing due in its window, making it easier to notice a slipped deadline or a thin governance structure — Techjoint files with a single listed officer, AKN Build with two — mattering more than turnover alone would suggest.
The wider point: a fiscal year end set once, often years before anyone thought to track it, quietly decides which companies stand out on a compliance calendar and which disappear into a 28-company pile-up. Knowing which group a company falls into changes how much attention its deadline deserves.