Tax Filing Singapore: How Companies Can Stay Compliant with IRAS

Navigating corporate tax obligations in Singapore is crucial for both locally incorporated businesses and foreign companies operating within its jurisdiction. With its competitive tax rates, robust compliance framework, and extensive network of double tax treaties, Singapore offers a pro-business environment, provided companies understand their tax responsibilities.

This guide breaks down everything you need to know from tax residency rules and exemptions to filing deadlines, GST compliance, and penalties. Read on to ensure your business stays compliant and maximises available tax reliefs.

Corporate Tax Obligations in Singapore

Understanding Singapore’s corporate tax system is essential whether you’re running a local company or managing foreign operations with income sourced from Singapore. All companies that earn income in Singapore, regardless of where they’re incorporated, must register with the Inland Revenue Authority of Singapore (IRAS) and file corporate income tax returns annually. 

The standard corporate income tax (CIT) rate is 17% on chargeable income, which is calculated after deducting allowable expenses and approved tax reliefs. Filing is mandatory even if the company does not owe any tax for that assessment year.

Singapore-Incorporated Companies (“Local Companies”)

Companies incorporated in Singapore under the Companies Act are generally considered local entities. These companies are regarded as tax resident if control and management—such as board decisions and strategic meetings—are conducted in Singapore.

Key benefits for Singapore tax-resident companies:

• Access to double tax treaties (DTAs)
• Start-up Tax Exemption scheme eligibility
• Partial tax exemptions

Even if a company is dormant or not generating income, it must continue to file tax returns unless IRAS grants a formal waiver. Failing to comply can lead to penalties and legal enforcement.

Foreign Companies or Branches Operating in Singapore

Foreign companies with operations in Singapore may take the form of either:

• A branch office of a foreign parent company (not a separate legal entity)
• A foreign-incorporated entity with Singapore-sourced income (e.g. from property or services)

These companies are taxed on income earned within Singapore. However, because their central management is usually outside Singapore, they are generally not considered tax residents.

Implications for foreign companies:

• Ineligible for Start-up Tax Exemption
• Cannot access tax-resident-only incentives
• Still enjoy partial tax exemptions on chargeable income
• Must fulfil annual tax filing obligations

Tax Residency Rules

Tax residency is determined not by place of incorporation but by where strategic decisions are made. For example:

• A Singapore-incorporated company managed entirely from abroad could be considered non-resident (rare but possible)
• A foreign-incorporated company may be considered resident if control and decision-making happen in Singapore

Why tax residency matters:

• Determines eligibility for tax treaty relief
• Enables exemptions for specific foreign income
• Impacts access to local tax incentive schemes

Types of Income Subject to Corporate Tax

Singapore companies are taxed on chargeable income derived from Singapore or foreign income remitted into Singapore. The main categories of taxable income include:

A. Trading and Operational Income

Revenue from sales, manufacturing, or services forms the core taxable income for most companies. Business-related expenses, like salaries, rent, and utilities, can be deducted to calculate net income. For instance, a logistics firm earning revenue from local deliveries would declare that as trading income.

B. Services and Consultancy Fees

Fees for services performed in Singapore are taxable. If services are partly rendered overseas, companies must apportion the income accordingly.

For example, a tech consultancy executing work in both Singapore and Malaysia must divide its income fairly between the two jurisdictions.

C. Rental Income

Companies earning rental income from properties or equipment must declare it as business income. Related expenses are deductible.

Deductible expenses include:

• Maintenance and repair costs
• Property taxes
• Mortgage interest on the property

D. Investment Income

Income from investments such as interest or royalties is generally taxable.

Exemptions include:

• Dividends from other Singapore tax-resident companies (exempt under the one-tier system)
• Foreign dividends, subject to conditions

E. Capital Gains

Capital gains, such as profits from selling long-term assets or investments, are not taxed in Singapore.

However, capital gains may be taxable if:

• The company is in the business of asset trading
• The transaction is frequent, short-term, or intended for resale

IRAS assesses such cases based on “badges of trade”:

• Frequency of transactions
• Length of asset holding
• Purpose at time of purchase

F. Foreign-Sourced Income

Singapore taxes foreign income only when it is received in Singapore, unless it is exempted.

Exempt foreign income includes:

• Foreign dividends
• Profits from foreign branches
• Overseas service income

To qualify for exemption under Section 13(8):

• The foreign income must be taxed at a rate of at least 15% in its source country
• The exemption must be deemed beneficial to the Singapore company by IRAS

With proper planning, many companies structure foreign earnings to meet these conditions and remit them into Singapore tax-free. Non-resident companies cannot access these exemptions and must manage tax via DTAs or offshore retention.

3. GST and Tax Filing – Key Points for Businesses

Goods and Services Tax (GST) is Singapore’s value-added tax. As of 1 January 2024, the rate stands at 9%. Businesses are only subject to GST obligations once they are registered with IRAS.

Registration and Thresholds

Businesses must register for GST if:

• Their taxable turnover exceeds S$1 million over the past 12 months (retrospective test)
• They reasonably expect it to exceed S$1 million in the next 12 months (prospective test)

Once a threshold is crossed, the business must register within 30 days. Failure to register can result in penalties, and IRAS may backdate the GST registration and require retroactive GST payment.

Voluntary GST Registration

Companies with turnover below the threshold may still choose to register voluntarily, especially if they mainly serve GST-registered clients and want to claim input tax

However, voluntarily registered businesses must:

• Stay registered for a minimum of 2 years
• Fully comply with GST rules, including invoicing, filing, and payment
• Factor in administrative and compliance costs

Filing GST Returns

GST-registered businesses must file Form F5 returns via the myTax Portal.

• Filing frequency: Usually quarterly, but monthly or annual filing may be approved in specific cases
• Due date: One month after each accounting period ends. For instance, if your quarter ends on 31 March, the return and payment are due by 30 April.

For a more detailed understanding of GST, from registration requirements and filing procedures to claiming input tax and meeting compliance obligations, we’ve prepared a separate article that breaks down everything you need to know. Explore our Complete GST Guide for Singapore Businesses to ensure you’re meeting IRAS expectations and making informed tax decisions.

Tax Filing Deadlines

To stay compliant with IRAS regulations, companies in Singapore must adhere to strict tax filing deadlines throughout the year. 

• Corporate Tax Return (Form C-S/C): All companies are required to file by November 30 each year. This applies to all financial year ends in the preceding calendar year (e.g., YA 2025 covers any FYE in 2024).
  
• Estimated Chargeable Income (ECI): Must be submitted within 3 months after the company’s financial year-end.
  
• GST Returns (if applicable): GST has separate quarterly deadlines and is not tied to the Form C-S/C filing.

Penalties for Late or Non-Filing

If your company fails to file its tax return by 30 November:

• Initial Consequences:
  
  • IRAS may issue an “Offer of Composition” with a fine between $300–$1,000 for first-time offences.
  • Fines can go up to $5,000 per offence.
  • You’ll be given a new deadline to file. Meeting it and paying the fine will usually avoid prosecution.
    
• If Ignored:
  
  • IRAS may issue an Estimated Notice of Assessment (NOA), requiring payment within one month.
  • Under Section 65B of the Income Tax Act, directors may be legally compelled to provide information.
  • Prosecution in court can follow, where higher penalties or even personal liability (fines or jail) for officers may apply.

Important Notes

• Dormant or ceased businesses are still required to file until they are officially struck off or wound up. “No business” is not a valid excuse.
  
• Failing to file the ECI or GST returns carries separate penalties.
  
• Extensions for corporate filings are rarely granted. If needed, a company or its tax agent must formally request an extension before 30 November, with valid reasons. Approval is not guaranteed.

How to File Your Taxes

Singapore’s tax filing system is streamlined and largely digital, catering to both individuals and businesses. The Inland Revenue Authority of Singapore (IRAS) manages all tax matters, with most filings done through the myTax Portal. Below is a comprehensive guide to the procedures, required documents, deadlines, and available platforms for corporate tax filing in Singapore.

Step 1: Understand Your Corporate Tax Obligations

Companies incorporated in Singapore are required to file their corporate income tax returns annually with the IRAS. The tax year follows the calendar year from 1 January to 31 December, and companies must file their Estimated Chargeable Income (ECI) within three months after their financial year-end. The actual tax return, using the appropriate form, must be submitted by 30 November each year.

• Companies pay tax on their net profits, which are calculated as gross income minus allowable business expenses.
• Companies registered for GST must also file separate GST returns.

Step 2: Gather Required Financial Documents

Before filing, collect all necessary financial documents to support your tax return. These include:

• Full financial statements, such as the balance sheet, income statement, and cash flow statement.
• Detailed tax computations showing income and deductible expenses.
• GST returns, if applicable.
• Company registration certificate and any other relevant business documents.

Step 3: Log in to the myTax Portal using CorpPass and Select the Appropriate Tax Form

Authorised company representatives must log in to the myTax Portal using CorpPass, a corporate digital identity system. Once logged in, select the correct tax form based on your company’s profile:

• Form C-S for small companies with annual revenue of S$5 million or less and meeting eligibility criteria.
• Form C-S (Lite) for companies with revenue up to S$200,000. Form C-S (Lite) only requires 6 essential fields (such as revenue and taxable income) and is designed to streamline filing for microenterprises.
• Form Cis the full-fledged return for companies that do not qualify for C-S. If your revenue is above $5 million, or you have complicated tax matters (e.g. need to claim foreign tax credits, have Singapore branch income of a foreign company, have investment income with different rates, etc.), you file Form C.

Step 4: Complete and Submit the Corporate Tax Return

Fill in the tax return form with accurate information from your financial documents. Many accounting software solutions now integrate with IRAS, enabling seamless filing and reducing errors and manual entry.

• Upload all required supporting documents if filing Form C.
• Review your entries carefully before submission.
• Submit your tax return electronically through the myTax Portal.

Step 5: Pay Your Corporate Tax and Keep Records

After IRAS processes your return, they will issue a Notice of Assessment by 31 May of the following year, indicating your tax liability.

• Corporate tax payments are due within 30 days from the NOA date.
• Maintain all financial and tax records for a minimum of five years for audit purposes.

Understanding the Notice of Assessment (NOA)

A Notice of Assessment (NOA) in Singapore is an official tax document issued by the Inland Revenue Authority of Singapore (IRAS) to inform taxpayers, both individuals and businesses, of their assessed taxable income and the corresponding tax amount payable or refundable for a specific Year of Assessment. Essentially, it serves as your formal tax bill, detailing the types and amounts of income taxed, deductions or reliefs claimed, and the final tax liability or refund due.

What Does the NOA Include?

The NOA provides a comprehensive summary of your tax position for the year. It includes:

• Your total chargeable income after deductions and reliefs.
• The amount of tax payable or refundable.
• Details of any adjustments made by IRAS based on information from your tax return or third-party data.
• Payment instructions and deadlines for settling any tax payable.

For employers, a similar NOA may relate to outstanding levies such as the Skills Development Levy (SDL), specifying amounts due and payment methods.

Types of Notices of Assessment

IRAS issues different types of NOAs depending on the taxpayer’s circumstances and filing status:

• Original NOA: Issued after IRAS processes your submitted tax return or auto-included income data. This is the standard tax bill reflecting your declared income and reliefs.
• Amended NOA: Issued when IRAS revises your assessment downward, for example, after accepting additional reliefs or correcting income figures.
• Additional NOA: Issued when IRAS increases your tax payable due to the withdrawal of reliefs or the inclusion of previously undeclared income.
• Estimated NOA: Sent if you fail to file your tax return by the deadline. IRAS estimates your tax based on available data and issues this provisional bill. You must still file your return to receive a final assessment.

For companies, there are four specific types of NOAs related to corporate tax filings:

• Type 1 NOA: Issued after submission of Estimated Chargeable Income (ECI).
• Type 2 NOA: Issued if ECI or tax returns are not filed on time or are understated.
• Type 3 NOA: Issued after successful filing of corporate tax returns (Form C or C-S).
• Type 4 NOA: The final assessment after IRAS completes its review, with a 2-month window to file objections.

Importance of the NOA

The NOA is a critical document because it confirms your tax obligations or refunds. It acts like an invoice, specifying the exact amount you owe or will be refunded. Taxpayers have a 30-day period from the NOA issuance date to file a formal objection if they disagree with the assessment. This ensures transparency and allows corrections before finalising tax liabilities.

Payment and Penalties

The NOA includes payment instructions and deadlines. Tax payments must be made within one month of the NOA date. IRAS accepts various payment methods, including GIRO, internet banking, cashier’s order, and others. Failure to pay on time may result in penalties, typically a 5% late payment surcharge on the outstanding amount.

Accessing Your NOA

You can access your NOA digitally via the IRAS myTax Portal by logging in with your Singpass or CorpPass. The portal allows you to view and print your current and past NOAs for up to four years. IRAS also sends physical copies by mail, although digital access is encouraged for convenience and speed. You can receive SMS notifications when your NOA is ready by updating your contact details with IRAS.