On 19 October 2026, the Inland Revenue Authority of Singapore (IRAS) announced a set of new and enhanced digital resources for corporate income tax filing, according to its media release on the YA 2026 filing season. More than 323,000 companies, including over 37,000 newly incorporated companies, are due to submit their Corporate Income Tax (CIT) Returns for Year of Assessment (YA) 2026 by 30 November.
The tools cover the full filing cycle, from checking whether a company must file, through preparing the tax computation, to tracking payment and objections afterwards. For company owners and directors, the practical question is which of these resources are useful, and what needs to happen in the weeks remaining before the deadline.
This article summarises the new IRAS resources, explains who must file, sets out the penalties for late submission, and gives a five-step preparation sequence.
Key Takeaways
IRAS has added or enhanced digital resources for each stage of corporate income tax filing in 2026: before filing, during preparation and submission, and after filing. Several tools are new this year, including checkers for filing obligations, expense deductibility, payment status and objection status.
The table below groups the resources by stage, based on the IRAS release.
Every company that receives a CIT filing obligation from IRAS must submit a return for YA 2026 by 30 November 2026. The 323,000 companies in scope include over 37,000 newly incorporated companies, which are companies in their first period after incorporation.
Newly incorporated companies are often unsure whether a return is due. Per IRAS, most close their first set of accounts in their second year of incorporation and are automatically issued tax returns. A minority close their first accounts in the year of incorporation, and those companies can now request their first return through a guided online form. The new Filing Obligations Checker on the IRAS Chatbot is designed to settle the question of whether and when to file.
Returns are filed on Form C-S, Form C-S (Lite) or Form C, depending on the company's circumstances. According to the release, Form C-S (Lite) reduces the requirement from three pages to six essential fields for companies with straightforward tax matters and annual revenue of S$200,000 or below. About 8 in 10 eligible companies used it in YA 2025. Companies can review the IRAS guidance on filing Form C-S, Form C-S (Lite) and Form C to see which form applies.
Filing a return is separate from reporting Estimated Chargeable Income (ECI), which has its own timeline. ATHR's guide on how to file ECI in Singapore explains how the two interact.
The tools with the greatest practical value are those that address the usual causes of delay: missing records, uncertain deductions and computation errors.
The Record Keeping Assistant helps companies gather business records into a single file before the tax computation begins. The Business Expense Deductibility Checker helps owners check whether an expense is deductible, which suits staff who do not have formal tax training. The Basic Tax Calculator guides the computation and schedules, with explanatory notes and validation checks that flag mistakes before submission.
Technical access problems also cause missed deadlines. The myTax Portal Troubleshooting Assistant provides step-by-step help with common login and access issues, so a director who has not logged in for a year can resolve access before the last week of November.
Self-service checkers answer general questions, while a company's own facts decide the treatment. Expenses with mixed business and personal use, overseas payments and related-party charges are typical items where a generic answer from a tool may not match the specific position, so a review by a tax professional is often worthwhile before submission.
IRAS reports that more than 90% of companies filed their YA 2025 returns on time. For the minority that did not, enforcement has been active. Since January 2026, IRAS has issued more than 4,100 Notices to Attend Court to companies that failed to file returns for YA 2025 and earlier years, with more than S$2 million in penalties collected.
The penalties for a company that misses the due date are:
IRAS reminds directors that they are responsible for accurate and on-time filing of their company's CIT Returns, and directs them to its companies tax filing resources. The IRAS page on late filing or non-filing of CIT Returns explains the process in more detail.
The IRAS release notes that, following Budget 2026 and the later support measures, companies may be eligible for the CIT Rebate, the CIT Rebate Cash Grant and the SME Cash Grant 2026. Companies considering AI expenditure may also look at the expanded support under the Enterprise Innovation Scheme (EIS) for qualifying AI expenditure in YA 2027 and YA 2028.
Rebate amounts and conditions are set by IRAS and should be confirmed from its summary of measures before filing. How the rebate interacts with the start-up tax exemption (SUTE) and its shareholder conditions is explained in ATHR's article on claiming the YA 2026 CIT rebate.
The following sequence suits most SMEs and founder-led companies.
Step 1: Confirm the filing obligation. Check the notice from IRAS or use the Filing Obligations Checker if the company is newly incorporated.
Step 2: Organise records. Gather financial statements, invoices, bank statements and supporting schedules in one file, using the Record Keeping Assistant if helpful.
Step 3: Prepare the tax computation. Use the Deductibility Checker and Basic Tax Calculator, and complete the relevant schedules for the form that applies.
Step 4: Test access and file. Confirm that the authorised person can log in to myTax Portal, then submit before 30 November. Leave time for any access problems.
Step 5: Track payment and status. After filing, use the Payment Status Checker to confirm processing timelines and any next steps.
Companies that anticipate needing to revise a return or lodge an objection should note that the digital submission service on myTax Portal becomes mandatory from 1 July 2027, so familiarity with it now will help.
The deadline for YA 2026 CIT Returns is 30 November 2026, according to IRAS. More than 323,000 companies, including over 37,000 newly incorporated companies, are due to file by that date.
IRAS states that a company that misses the due date can be fined up to S$5,000, with additional daily penalties of S$100 for continued non-compliance. Repeated failure to file over two or more years can result in a court-ordered penalty of twice the tax assessed.
It depends on when the company closes its first accounts. Most close them in the second year after incorporation and are issued returns automatically. IRAS has added a Filing Obligations Checker on its Chatbot to confirm whether and when a newly incorporated company must file.
Form C-S (Lite) is a simplified return with six essential fields, for companies with straightforward tax matters and annual revenue of S$200,000 or below. IRAS reports that about 8 in 10 eligible companies used it in YA 2025.
The 2026 filing season brings more self-service support than earlier years, with checkers and guides at every stage, but the responsibility for an accurate and timely return stays with the directors. A missed deadline carries a fine of up to S$5,000 and potentially daily penalties, and IRAS has shown it is willing to pursue court action for repeated non-filing.
Companies that confirm their obligation, organise records early and test portal access well before 30 November leave the most room to correct problems.
Preparing a tax return depends on clean accounts, accurate records and timely submission, and these tend to slip when a small team is also running daily operations.
ATHR supports Singapore companies with accounting and tax services covering tax computation and filing, and with bookkeeping that keeps records organised year-round.
👉 Ready to prepare your corporate tax filing with confidence? Book a free consultation with ATHR today →
Information based on the IRAS media release dated 19 October 2026. Filing requirements and support measures may change, so confirm current details with IRAS before filing.
The ATHR Content Team is a group of professional writers from Singapore and the Philippines, committed to delivering informative, practical, and engaging content for business owners across Southeast Asia.
