Profits Tax Deadlines: N, D, M Codes and Block Extension

At a glance

The actual extended dates are published each year by the IRD in a circular letter. The table above shows the structure; the specific dates are as published for that year.

How are the three codes assigned?

Simply: by your company’s year end (the last day of the accounting year).

• Year end between 1 April and 30 November → code N
• Year end 31 December → code D
• Year end between 1 January and 31 March → code M

The most common in Hong Kong are 31 December (D) and 31 March (M).

This is not a minor detail — code M gives roughly three months more than code D, and code N essentially gives no extension at all. The moment you choose a year end you have decided how much time you get each year to close the books.

If your company has not fixed a year end yet, or you want to change it, start with choosing a year end.

A concrete example

For the 2025/26 year of assessment, the block extension dates published by the IRD were:

• N: 2 May
• D: 17 August
• M: 16 November
• M, loss cases: extendable again to 1 February 2027

These dates change every year (they avoid weekends and holidays), so do not memorise one — follow the IRD’s circular for the year.

The block extension has a precondition: a tax representative

Plenty of people assume it is automatic.

The block extension scheme applies only to companies that have appointed a tax representative. Dealing with the IRD yourself, without a representative, means no block extension — the deadline is the one printed on the return, generally one month from the date of issue.

And from April 2026, tax representatives must submit block extension applications electronically through the IRD’s Tax Representatives’ Portal. So this is something the representative does for you, not a paper form you send yourself.

How does a new company’s first return work?

A new company does not receive a return immediately — the first one is issued some time after incorporation, and it usually comes with a longer filing period.

But note two things:

1. The actual deadline is the one printed on the return. Do not work it out yourself from the general rule.

2. The first return may cover more than 12 months (from incorporation to the first year end). That directly affects the scope of the audit you need to prepare.

The full preparation for a first return is in filing your first tax return.

The line that matters most: an extension delays the form, not the tax

This is the most expensive misconception.

An extension means you file the return later; but the payment deadline once the assessment is raised does not move with it. And during the extension, provisional tax arrangements carry on as normal.

So “we got an extension, no need to set money aside yet” is a costly way to think about it — the time loosened, the cash flow requirement did not.

What happens if you miss it?

If the return is not filed by the deadline, the IRD can:

• Issue an estimated assessment — tax on the IRD’s own estimate of profits, usually not in your favour
• Issue a penalty notice or bring a prosecution
• Charge additional tax under the Inland Revenue Ordinance

The consequences and remedies in detail: filing a return late.

In practice there are only three things to do

1. Confirm which code your company is — look at the year end.

2. Put that year’s deadline in the calendar at the start of the year, rather than waiting for the return to arrive.

3. Work backwards from it. An audit usually takes weeks to months, so the books have to be finished well before the deadline. The real deadline is “when the books have to be complete”, not “when the return is due”.

Want someone to line up the year end, the audit and the filing together and track the deadlines each year? Talk to us, or get started.

This article is general information and does not constitute tax advice. The year-end code classification, block extension dates and filing requirements are as published by the IRD in its annual circular letter and latest guidance.