How to File a Hong Kong Profits Tax Return (BIR51): What to Submit, When and How
Every Hong Kong company that the Inland Revenue Department asks will file a profits tax return, form BIR51 for a corporation, once a year, even if it made a loss or had no business. It's less complicated than it looks, if the accounts are ready. Here's the whole process, in order.
1. The return arrives
- Each year, the IRD issues returns in bulk on the first working day of April, for the year of assessment that has just ended.
- A new company generally receives its first return about 18 months after incorporation.
- If you never received one but the company is chargeable to profits tax, you must tell the IRD in writing within four months after the end of the basis period (section 51(2) of the Inland Revenue Ordinance). Not receiving a return doesn't mean nothing is owed.
2. Get the accounts ready
The return is built on the company's financial statements for the accounting period ending in the year of assessment. They need to be audited first (see audit-ready books and the year-end checklist).
3. Prepare the tax computation
The tax computation takes the accounting profit and adjusts it to assessable profit:
- adds back what isn't deductible: private spending, capital items, depreciation, donations, profits tax (see tax-deductible expenses);
- deducts what's allowed separately: depreciation allowances and approved donations (see fixed assets and depreciation);
- deducts any losses brought forward.
The result is taxed at the two-tiered rates, if the company can use them; the return is also where a company with connected entities makes the election.
4. Complete the return and attach the documents
The return asks for the company's details, its accounting period, the assessable profit or loss from the computation, and a series of questions about the business. With it go the supporting documents listed in the form:
- the certified statement of financial position and statement of comprehensive income (profit and loss) for the basis period;
- the auditor's report;
- the tax computation, with schedules showing how the assessable profit or loss was arrived at.
5. File it
- On paper, signed by an authorised person and posted with the documents.
- Electronically, through the IRD's online services, where the financial statements and tax computation are submitted in iXBRL format (see filing in iXBRL).
6. Meet the deadline
The return states its due date, generally one month from the date of issue. Companies with a tax representative usually have longer under the IRD's block extension, depending on the year end (see profits tax return deadlines). Your year end decides which date applies (see financial year end).
If you're late
Failing without reasonable excuse to file a return when required can lead to additional tax of up to three times the tax undercharged (section 82A), or prosecution instead. The same applies to failing to tell the IRD that the company is chargeable when no return was issued. If you can't make the date, ask for an extension before it passes, not after.
7. After filing
- The assessment arrives with the final tax for the year and, usually, provisional tax for the next.
- Check it against the computation, and diarise the payment dates.
- Keep the records for at least seven years (section 51C).
How Certanta helps
- Books current all year, so the accounts are ready for the auditor soon after the year end.
- The return and the tax computation prepared from your books, included on monthly plans (see pricing). You review, sign and file.
- The deadline in your portal, under the IRD's dates for your year end, marked off when filed.
Frequently asked questions
When does a Hong Kong company receive its profits tax return?
The IRD issues profits tax returns in bulk on the first working day of April each year. A newly incorporated company generally receives its first return about 18 months after incorporation.
What if my company never received a profits tax return?
If the company is chargeable to profits tax, it must inform the IRD in writing within four months after the end of the basis period for the year of assessment (Inland Revenue Ordinance, section 51(2)).
What documents must be filed with the profits tax return?
The certified statement of financial position and statement of comprehensive income for the basis period, the auditor's report, and the tax computation with schedules showing how the assessable profit or loss was arrived at.
Do small companies still need to submit financial statements?
Yes. The IRD has said that small corporations and businesses with gross income not exceeding HK$2 million are no longer permitted to file profits tax returns without supporting documents; if there was gross income, the financial statements and tax computation must be submitted.
When is the profits tax return due?
Generally within one month of the date of issue, as stated on the return. Companies with a tax representative usually have longer under the IRD's block extension scheme, depending on their accounting year end.
What happens if a profits tax return is filed late?
Failing without reasonable excuse to comply with a notice to file a return can lead to additional tax of up to three times the tax undercharged under section 82A of the Inland Revenue Ordinance, or prosecution.
The return prepared from books you can trust
Certanta prepares your profits tax return and tax computation from books kept current all year, included on monthly plans. You review, sign and file.
Open the demo See pricingThis article summarises the Inland Revenue Ordinance (Cap. 112) as published on e-Legislation and the IRD's published guidance, as at 29 October 2026. It is general information, not tax advice. Forms and filing arrangements change each year; follow the notes that come with your own return.