Module 8: Filing and deadlines

Deadlines decide more claims than definitions do. A project can be eligible, costed and documented and still produce nothing because a registration window closed or a form was not in with the return. This module gives a way to think about dates that works in all seven countries: three kinds of deadline, each tied to the year end, laid onto one calendar. After it you will be able to build that calendar for your own year end and know which dates cannot be moved.

What this module covers

The three kinds of deadline: before the claim, with the claim, and after the claim.
Why the "before" deadlines are the dangerous ones.
What the forms ask finance to have ready.
A claim calendar built from the year end, with the dependencies between steps.
The deadline and form facts for each of the seven countries.

Three kinds of deadline

Before the claim

Some schemes require a step before the claim can be made: registration or approval of the activities, or notification that a claim is coming. Where the step is mandatory, missing it generally removes the right to claim for that year, and nothing in the costing or documentation can recover it. Across the seven countries, one requires a kind of approval application before the income year even ends, several set a window of three to ten months after year end, two ask for advance notice only from first-time or returning claimants, and three have no step at all.

With the claim

Every scheme delivers the claim through the tax return: in the return itself, on a schedule or form with it, or in a supplementary return filed shortly after. Three dates sit here: the return's due date, the form's due date where it differs, and the final date by which the claim can be made or amended. In some countries that final date is the return date; in others it is a fixed period after the period end or the return due date, which allows a claim to be added to a return already filed.

After the claim

The tax authority has a period in which it can ask questions or amend the assessment, and the company a period in which records must be kept; across the seven countries these run from three to seven years. Module 9 covers that period. For the calendar, the records folder closes only when the last period has run.

Forms and what they ask finance to have ready

The form is the scheme's view of the claim, and its structure tells you what to prepare. In different orders and depth, the forms ask for some or all of five things: a description of each project and its uncertainty, the costs by category and by project, the method used to apportion staff costs, the people responsible for the claim and any advisor who helped, and the calculation. Where a form sets word limits, the narrative is written to them; where it asks about each project, the candidate list from module 7 must have one row per project.

A claim calendar built from the year end

Lay the claim out in months from the year end, then overlay the country's fixed dates from the table below. Dependencies matter more than dates: costing cannot finish before the candidate list is settled, and the form cannot be filed before the costing.

Months from year end	Step	Owner
Before year end	Lodge any approval or finding application due before year end; check whether a notification step applies	Tax lead
0 to 1	Close the ledger; freeze the cost pool; extract staff costs by person	Finance
1 to 2	Workshop and interviews; candidate list signed off by the engineers	Finance with technical leads
2 to 3	Any post year end approval or registration application prepared from the candidate list	Tax lead
3 to 5	Costing and the five-step calculation of module 6	Finance
5 to 6	Pre-claim review of each project (module 9); exclusion memos; narrative drafted to the form's limits	Tax lead and technical leads
6 to 9	Notification or registration lodged where the window runs after year end; form and return prepared; elections minuted	Tax lead
Return date	Return, schedule or form filed; any supplementary return or payout application that must follow	Tax lead
After filing	Diary the amendment deadline and the end of the assessment period; archive the records folder	Finance

Two rules keep the calendar honest. Put every "before" deadline in the company's statutory calendar, owned by a named person, not in the R&D project file. And where the country allows the claim to be made after the return, treat that as a safety margin, not a plan.

Illustrative example

Illustrative example. Harbour Robotics Ltd, a hypothetical company, has a 31 December year end and claims in the United Kingdom and in Canada. For the year ending 31 December 2026 the calendar reads as follows. United Kingdom: a first-time or returning claimant must tell the tax authority within 6 months of the end of the period of account, by 30 June 2027; the Company Tax Return is due 12 months after the end of the accounting period, 31 December 2027; the claim must be made, amended or withdrawn within 2 years of the end of the accounting period, 31 December 2028; and the detailed information form goes in before the return, or the claim is removed. Canada: there is no registration; the corporate return is due six months after year end, 30 June 2027; the claim is filed with the return and no later than 12 months after its filing due date, 30 June 2028; an expenditure not identified on the prescribed form by that date cannot earn the credit, and there is no discretion to extend. The finance lead diaries 30 June 2027 and 30 June 2028, aims to close the costing by 31 May 2027, and treats the UK two-year window as margin. Detail: Deadlines: United Kingdom and Deadlines: Canada.

Across the seven countries

Each row uses register wording; the deadlines page holds the detail.

Country	Before the claim	The claim and its form	Claim deadline
United States	No pre-registration.	Form 6765, filed with the income tax return. Calendar-year C corporation returns are due on the 15th day of the fourth month after year end, with a six-month extension.	Within three years from the time the return was filed or two years from the time the tax was paid, whichever is later.
United Kingdom	Claim notification within 6 months of the end of the period of account, if claiming for the first time or the last claim was more than 3 years ago.	In the Company Tax Return, due 12 months after the end of the accounting period; an additional information form before the return.	Made, amended or withdrawn within 2 years of the end of the accounting period it relates to.
Ireland	Notify Revenue in advance, at least 90 days before the claim, using a prescribed form, if claiming for the first time or no claim in the previous 3 years.	The research and development panel of the Form CT1, due by the 23rd day of the ninth month after the end of the accounting period where filed electronically.	Within 12 months of the end of the accounting period in which the expenditure was incurred.
Canada	No registration. Optional pre-claim approval has been available since 1 April 2026.	Form T661, with Schedule 31 for corporations, filed with the income tax return, due six months after the tax year end.	12 months after the return's filing due date, 18 months after year end for a corporation.
Australia	Register R&D activities with the department within 10 months of the end of the income year, every year. Advance and Overseas Finding applications before the income year ends.	The R&D tax incentive schedule with the company tax return, due between 31 October and 15 May depending on the entity and lodgement route.	Register within 10 months of year end, then claim in the company tax return.
New Zealand	General approval by the last day of the 3rd month after the end of the income year. Criteria and methodologies approval applications by the last day of the 6th month before the end of the first income year they relate to.	The R&D supplementary return, filed through myIR after the income tax return for the year.	Within 30 days after the income tax return due date, or the extension of time due date.
Singapore	No registration.	The corporate income tax return (Form C-S or Form C), filing due date 30 November of the Year of Assessment; any cash payout application after filing and before that date.	Filing due date of the tax return.

Where to go next

Annual registration: Australia.
General approval: New Zealand.
Advance notification: United Kingdom.
Module 1: Scheme mechanics, when the benefit arrives.
In-House Finance Team Program overview and country tracks.