Missed deadlines across a client book are almost never a calendar failure. They are a register failure — the obligation was never on the list, because the list was copied from last year and last year was already incomplete.
Key takeaways
Create one row for every combination of client, obligation and period, generated from the rules rather than from history: entity type, year-end, and the obligations that follow from those two facts. Then reconcile that generated register against what your practice-management system actually has, and work the exceptions. A model is good at both halves — deriving the obligations from structured client attributes, and diffing two lists that use different names for the same thing.
The filing itself, any extension or relief request, and the signature remain with the professional. What you are automating is the question “is anything missing”, which is the question nobody has time to ask.
subsection 150(1) of the Income Tax Act requires a return for each taxation year: for a corporation, within six months after the end of the year where the listed conditions apply; for an estate or trust, within 90 days from the end of the year; for an individual, on or before the following April 30, or June 15 where the individual carried on a business in the year or was at any time in the year the cohabiting spouse or common-law partner of such an individual. Those are structural rules. Given entity type and year-end, the due date follows without anyone remembering it.
Information returns sit on a separate track: section 205 of the Income Tax Regulations requires returns under that Part to be filed without notice or demand and, unless otherwise specifically provided, on or before the last day of February in respect of the preceding calendar year, with a 30-day rule where a business or activity is discontinued. GST/HST returns run to their own filing periods under section 238 of the Excise Tax Act. Non-tax obligations — corporate annual returns, regulatory filings, insurance renewals — belong on the same register even though they come from elsewhere.
Everything consequential. Whether relief is worth requesting, whether a filing position holds, whether an extension is available, and whether the return is correct are professional judgments. The register tells you a return is due; it does not tell you the return is right. The penalty regime in section 162 is the reason the register exists, but it is also a reminder that the cost of a wrong filing is not limited to lateness.
Nor should an automated system file anything. The value is in never being surprised, not in removing the human from the submission.
Changed facts. A client incorporates mid-year, changes its year-end, winds up a subsidiary, or acquires payroll obligations, and tells you months later. A register generated from last year’s list will never contain the new obligation, because the list has no mechanism for growth. A register generated from client attributes will, provided the attributes are refreshed — which is why the annual engagement refresh should update entity data as a matter of course rather than only confirming the fee.
The related discipline is retention. section 230 of the Income Tax Act requires records and books of account, together with the accounts and vouchers necessary to verify them, to be retained until six years from the end of the last taxation year to which they relate, and electronic records to be kept in an electronically readable format. The register should carry the retention clock as well as the filing clock, so files are not destroyed early and not kept forever by default. Treadstone Law’s note on corporate record retention in Ontario covers the obligations that sit alongside the tax rule.
If a deadline is missed, the question of what happens next has its own timing. In Ontario the basic limitation period is two years running from discovery, as Treadstone Law explains in its answer on the basic limitation period, and its note on what has to be proven in a professional negligence claim against an accountant sets out the elements. Limitation rules vary by province and by claim, so take advice on your own facts. The practical point for the register is that a missed obligation should generate a dated internal record at the moment it is discovered.
A three-partner practice in Manitoba services roughly 400 client entities. The deadline list is a spreadsheet, rolled forward each year and edited by three people.
The firm rebuilds it. Entity type, year-end and registered accounts are extracted from the prior year’s filings and the engagement letters; a model derives the obligation rows from those attributes and diffs the result against the spreadsheet. The diff is the whole story. A handful of corporations acquired mid-year have no rows at all. Several rows exist for entities that were wound up two years ago. A number of dates disagree between the spreadsheet and the derived register, and in each case the derived date is the one that follows from the year-end on file.
Nothing is filed automatically. The exceptions are worked by a manager over two weeks, the entity data is corrected at source, and the annual engagement refresh is changed so that entity attributes are confirmed rather than assumed. The following year the diff is short, which is the point.
Measure obligations discovered by reconciliation, filings made more than a week before the due date, penalty assessments, and the number of client-attribute corrections per cycle. Those tell you whether the register is real.
This page is written for a firm that delivers work to a book of clients. If the question is really about the front desk — intake, scheduling, recall and reminders — that lives on the professional practice owners page. If it is about your own month-end, reconciliation and payables rather than what you deliver to clients, that is accounting automation, or bookkeeping automation for coding and receipt capture. The tooling overlaps; the risk almost never does.
Can the system file on our behalf if nobody acts?
No. A filing is a professional act with a signature attached. Escalate to a person, and escalate earlier than feels necessary.
Is a generic calendar or task tool enough?
A calendar holds dates. The problem is knowing which dates should exist, which is a derivation from client attributes. Keep the derivation and the reminders separate: derive the register, then push it into whatever tool your team already opens.
Should the register cover non-tax deadlines?
Yes. Corporate annual returns, regulatory filings, licence and insurance renewals and contractual review dates all fail the same way. One register with one owner beats four lists with none.
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