Corporate Tax Filing Singapore | Form C & Form C-S Services

A business owner from Woodlands called me in mid-November last year. "My company's tax filing is due November 30," he said. "I haven't started yet. Can you help?"

This happens every year. Business owners get the IRAS notice in October. They think "I have time." Then suddenly it's mid-November and panic sets in.

We took on his filing. His financial statements were ready but his previous accountant had never explained what Form C-S meant or how tax computation works. He'd been guessing his way through tax filing for three years. Probably overpaying because he didn't know what expenses were deductible.

We prepared his tax computation properly, claimed all available deductions, and filed before the deadline. His tax bill dropped by $8,000 compared to the previous year - not because he made less profit, but because we claimed deductions he'd been missing.

Corporate tax filing in Singapore isn't just about filling in forms. It's about knowing what's deductible, what's not, and how to structure your tax computation to minimize your bill legally. This page explains how corporate tax filing works, the deadlines, and what you need to know.

What Corporate Tax Filing Actually Means

Every Singapore company must file a tax return annually with IRAS. This tells the government how much profit you made and how much corporate income tax you owe.

Singapore has two types of corporate tax returns:

Form C-S (Simplified): For smaller companies with revenue under $5 million, not claiming certain deductions, and not part of a group relief claim. Simpler form, less detail required.

Form C (Full): For larger companies, those claiming specific deductions (like foreign tax credit or group relief), or those with more complex tax situations. Requires detailed schedules and supporting information.

Both forms need a tax computation showing how you get from accounting profit to taxable income. This isn't the same number. Accounting profit includes non-deductible items. Tax computation adjusts for these.

A trading company in Jurong filed Form C-S for three years. In year four, their revenue hit $5.2 million. They had to file Form C instead. They didn't know this and filed Form C-S again. IRAS rejected it. We had to redo everything as Form C and refile. Delayed their tax clearance by six weeks.

Corporate Tax Filing Deadlines

IRAS has strict deadlines. Miss them and you face penalties.

ECI Filing: Within 3 months of your financial year end, you must file your Estimated Chargeable Income (ECI). This is your estimated taxable profit for the year. If you don't file ECI, IRAS will make their own estimate and it's usually higher than reality.

Form C-S/Form C Filing: By November 30 if filing by paper, or December 15 if e-filing. This is for financial years ending in the previous calendar year.

Example timeline: Your financial year ends December 31, 2024. You file ECI by March 31, 2025 (estimated tax). You file Form C-S/Form C by November 30, 2025 (actual tax return with audited numbers).

Most companies e-file to get the extra two weeks. There's no good reason to paper file in 2025.

Tax Preparation Service Process

Professional tax preparation means more than just filling in forms. Here's what proper corporate tax filing involves:

Step 1: Review Financial Statements

Your financial statements show accounting profit. We review them to identify tax adjustments. Did you record capital expenditure that qualifies for capital allowances? Are there non-deductible expenses? Is revenue recognized correctly for tax purposes?

Step 2: Prepare Tax Computation

Start with accounting profit. Add back non-deductible expenses (fines, penalties, private expenses). Deduct capital allowances on equipment and vehicles. Adjust for any timing differences. Result is taxable income (chargeable income).

Step 3: Calculate Tax Payable

Apply corporate tax rate (17% on most income). Apply tax exemptions if you qualify. Subtract any foreign tax credits. Result is tax payable.

Step 4: Complete Form C-S or Form C

Enter all required information. For Form C, prepare supporting schedules. Attach financial statements and other required documents.

Step 5: E-file and Pay

Submit through IRAS portal. Pay tax by the deadline IRAS gives you (usually within one month of assessment).

A construction company in Tampines tried filing their own Form C. They didn't know how to calculate capital allowances on their vehicles and equipment. Left that section blank. IRAS rejected the filing. We had to redo it properly. They overpaid $15,000 in tax because they didn't claim allowances they were entitled to.

Accounting Firm Expertise in Tax Filing

Not all accountants are equally good at tax. Some firms just do bookkeeping and treat tax filing as an afterthought. Here's what professional tax expertise looks like:

We Know What's Deductible: IRAS rules on deductibility are detailed. Entertainment expenses? 50% deductible for corporate gifts, but client entertainment isn't deductible at all. Renovation expenses? Deductible over three years. Staff training? Fully deductible. We know these rules.

We Claim All Allowances: Capital allowances on equipment (one year, three years, or more depending on asset type). Intellectual property allowances. Land intensification allowances if you renovate industrial buildings. Most companies miss some of these.

We Minimize Adjustments: Accounting profit and taxable profit differ because of timing. We structure your accounts to minimize these differences where possible, reducing tax in early years.

We Handle IRAS Queries: Sometimes IRAS asks questions about your tax return. We respond professionally with proper supporting documents. We've dealt with thousands of IRAS queries. We know what they're looking for.

One client's previous accountant claimed 100% of their renovation expenses in year one. Wrong. Renovation must be spread over three years. IRAS caught this and assessed additional tax plus penalties. We had to amend three years of tax returns to fix the error.

Bookkeeping Service Impact on Tax Filing

Good bookkeeping makes tax filing easier, faster, and cheaper. Bad bookkeeping makes it expensive and error-prone.

If you do monthly bookkeeping with us, your accounts are always organized. When tax filing time comes, we have clean data. Tax computation is straightforward. Filing is quick.

If you only come once a year with a shoebox of receipts, we need to reconstruct your entire year before we can even start tax filing. This costs more and takes longer.

Specific bookkeeping items that affect tax:

• Fixed Asset Register: Track all equipment, vehicles, computers purchased. Need this to calculate capital allowances correctly.
• Director's Loan Account: Money taken out or put in by directors. Needs to be recorded correctly for tax purposes.
• Revenue Recognition: When do you recognize revenue? Cash basis? Accrual? This affects taxable income.
• Expense Classification: Capital expenses vs revenue expenses. Deductible vs non-deductible. Proper classification saves tax.

An e-commerce business in Bedok kept terrible books. When we prepared their tax return, we couldn't tell which expenses were business vs personal. Had to treat questionable items as non-deductible to be safe. Probably overpaid $4,000 in tax because of poor bookkeeping.

Chartered Accountant Tax Knowledge

Chartered accountants study tax in depth. We know the Income Tax Act. We know IRAS guidelines. We stay updated on tax changes.

Recent tax changes that affect corporate tax filing:

Tax Exemption Changes: IRAS updated the partial tax exemption scheme for new companies. We make sure you claim the right exemptions.

Capital Allowances: Enhanced capital allowances for automation equipment were extended. We know which assets qualify.

Transfer Pricing: New rules for related party transactions. If you buy from or sell to related companies, proper transfer pricing documentation is needed.

A property company claimed new company tax exemption for five years. They didn't know the exemption changed after three years. We caught this during review and corrected before filing. Saved them from IRAS penalties.

Tax Advisor Strategic Planning

Tax advisors do more than just file tax returns. We help you plan to minimize tax legally.

Tax planning opportunities we identify:

Timing of Expenses: Should you buy that equipment in December or January? Timing affects which year you claim capital allowances.

Director Remuneration Structure: Pay directors via salary, bonus, or dividends? Each has different tax implications.

Group Relief: If you have multiple related companies, losses in one can offset profits in another. But you need to plan this properly.

Unutilized Items: Do you have unutilized capital allowances or losses carried forward? We make sure you don't forget to use them.

A logistics company was about to pay $180,000 in corporate tax. We reviewed their group structure and found they could claim group relief. Another group company had losses. We claimed group relief and reduced the tax bill to $120,000. Legal. Proper. Just needed proper planning.

Form C-S vs Form C: Which One You Need

Many companies don't know which form to file. Here's how to decide:

File Form C-S if ALL these apply:

• Revenue is $5 million or less
• You're not claiming group relief
• You're not claiming foreign tax credit
• You're not claiming enhanced deductions
• You're not part of a consolidated filing

File Form C if ANY of these apply:

• Revenue exceeds $5 million
• You want to claim group relief
• You have foreign income and want foreign tax credit
• You're claiming certain enhanced deductions
• You're part of a transfer pricing arrangement

Form C-S is simpler and faster but has limitations. Form C is more detailed but gives you more flexibility in what you can claim.

Common Corporate Tax Filing Mistakes

Here are errors we see often:

Missing ECI Filing: Companies forget to file ECI within 3 months of year-end. IRAS then estimates your income (always high). You have to object and prove actual income. Extra hassle.

Wrong Form Filed: Filing Form C-S when you should file Form C (or vice versa). IRAS rejects it. You refile. Delays everything.

Personal Expenses as Business: Owner's personal car expenses, family holiday, home internet. These aren't deductible. If IRAS audits and finds these, you pay additional tax plus penalties.

Missing Capital Allowances: Not claiming allowances on equipment, computers, vehicles. You're paying more tax than necessary.

Late Filing: Missing the November 30 / December 15 deadline. Late filing penalty is $200. If you're habitually late, penalty increases.

A trading company in CBD missed their filing deadline three years in a row. Third year, IRAS increased their penalty to $500 and sent a warning letter. They switched to us. We've filed on time for two years now. No more penalties.

What Corporate Tax Filing Actually Costs

• Form C-S Filing: $600-$1,200
• Form C Filing: $1,200-$3,000
• ECI Filing: $300-$600

Price depends on:

• Company size and complexity
• Quality of your bookkeeping
• How many adjustments are needed
• Whether we need to prepare financial statements too
• Timing (rush filings cost more)

If your books are clean and financial statements are ready, tax filing is straightforward and costs less. If we need to clean up your books first, costs increase.

Some companies try to save $600-1,200 by doing tax filing themselves. Then they miss $5,000-10,000 in legitimate deductions because they don't know tax rules. That's expensive savings.

Getting Your Corporate Tax Filed

Here's what we need from you:

• Financial statements (audited if required)
• Trial balance or detailed bookkeeping records
• Fixed asset register
• Details of any related party transactions
• Prior year's tax assessment
• Any foreign income details

We'll review everything, prepare tax computation, complete the form, and e-file before the deadline.

Typical timeline: If you give us complete information by end of October, we file by mid-November. No stress. No rush. Plenty of buffer before deadline.

Why Companies Choose Us for Tax Filing

"You found $8,000 in missed deductions my previous accountant never claimed. Paid for your fees five times over."

"You explained what every line in my tax computation means. First accountant who actually educated me."

"Three years of late filing penalties. You've filed on time every year since. No more IRAS warning letters."

"IRAS audit - you handled everything. Answered all queries. No additional tax assessed."

We're a team of ACCA and SQP top graduates, ex-Big 4 audit managers, and Singapore Chartered Accountants. We've filed thousands of corporate tax returns. We know IRAS procedures. We respond within 1 hour. We file on time, every time.