Eligibility, preparation and deadline
Updated 15 May 2026, fourteen pages and forty-nine questions. Singapore businesses report annually through C-S/Lite/C. C-S requires Singapore incorporation, revenue ≤ S$5 million, 17%-taxable income and no carry-back, group relief, investment allowance, FTC or source-deducted-tax claim; eligible revenue ≤ 200,000 permits Lite from YA 2020. Others use C. The FAQ links a separate preparation-document checklist. Estimated completion is thirty minutes; annual deadline 30 November. Corppass Corporate Tax (Filing and Applications) Approver may complete/approve/file; Preparer only sends to Approver.
Navigation, iHelp and conditional fields
Click iHelp beside an item for guidance. Use section tabs or bottom Next/Back; moving between sections auto-saves entries. Do not use the browser Back button. Fields start at zero; fill applicable nonzero information, with prompts for missing fields. Disabled fields are intentionally irrelevant under current answers, not necessarily errors. Fifteen minutes inactive prompts for a response within two minutes before logout.
Reviewer identity and responsibility
From YA 2021 IRAS uses SCTP reviewer information for profiling. Accredited Income Tax Advisor/Practitioner supplies name and a membership number of three letters plus four digits, e.g. ATA 1234; IRAS may verify it. If no such review or name/number unavailable, choose No. Company remains responsible for accurate complete returns. Director preparing/reviewing, or reviewing accounts-officer work, is reviewer. Finance manager reviewing before director endorsement may be named, or director. Agent manager reviewing before director submission or agent-partner endorsement is reviewer. Where company files the agent’s reviewed outcome unchanged use manager; otherwise name company personnel reviewing its changed position. Multiple accredited reviewers: disclose any one.
Pre-filled amounts and disputes
From YA 2018 pre-filled balances cover allowances, losses, donations and investment allowances brought forward, plus current donations. Use preceding-YA last assessment even under objection/query; if that assessment is not finalised the FAQ uses preceding-return declarations. Company’s Declaration may replace brought balances with company records including disputed figures. Update non-SGD functional currency in Corporate Profile first.
Donation discrepancies
View Donations follows IPC records and the financial period. A later receipt may belong to another YA; missing UEN must be corrected with institution, after which IRAS amends on receiving updated data. When visible donations and a non-SGD functional currency are involved, update functional currency first to enable a higher SGD-equivalent declaration. Do not simply override an unexplained IPC mismatch.
Long first accounts and group relief
For accounts 1 April 2024–31 December 2025, General Info shows whole period but subsequent assessment fields allocate profits/losses to YAs 2025/2026, usually ≤ 12 months each; time apportionment if no direct allocation. Transferor enters Assessment 1 Box 5, claimant Box 9, unlocking Group Relief. Complete electronically; no separate paper GR-A/B.
Drafts, approval and final filing
Save Draft at bottom and auto-save between sections. Retained twenty-one days or until 30 November, whichever later, without extending deadline. No approval alert: Preparer informs Approver. To amend pending return, Approver retrieves/saves as draft to restore Preparer rights or edits directly. Confirmation consolidates all entries including zero/NA for review; acknowledgement confirms actual filing and shows only populated fields. Submitted entries cannot be edited in that form; later corrections use revision service.
All required documents and separate submission
Normally attach financial statements, tax computation and schedules including Detailed P&L; applicable 19B IPR declaration, R&D claim, revised computation for carry-back/prior unreported income, and RPT. From YA 2020 RPT forms part of C: Box 31 Yes unlocks it. If documents cannot accompany filing, Corporate Tax → Submit Document must receive them by 30 November. Confirmation-page Submit Document uploads by category. Both roles upload; only Approver files to IRAS.
ACRA financial statements and one-file categories
Received (ACRA) means full XBRL financial statements already with ACRA and no duplicate financial-statement upload required. Detailed P&L is still needed with Original Tax Computation and Supporting Schedules. Otherwise attach P&L to financial statements or computation in respective category. Only one PDF under Original TC category: merge computation/schedules first. The PDF points to question 32 for a merging guide though the actual merging question is 35; follow the subject rather than that cross-reference.
Size limits and permitted PDF format
Each original/revised computation and schedules, financial statements or historical standalone RPT file ≤ 4 MB; 19B declaration and R&D form ≤ 2 MB. Only non-fillable PDFs. The source specifically instructs File → Print → Microsoft Print to PDF for Excel, Word or fillable PDF to remove active content such as e-signatures, not Save As PDF. Reduce readable scans to black-and-white 100 dpi or lower suitable resolution. Its question 39 reference to question 37 for conversion is misplaced: conversion is question 40.
All document status meanings
Submit Document: Pending=no upload; Pending Approval=awaiting review; Processing=transmission; Received=submitted. After three working days View Corporate Tax Filing Status also shows Ready to file=no document uploaded, Received=submitted, Not required=no submission required. Distinguish upload, approval and final receipt rather than treating Pending Approval as completion.
Return and document submission errors
Check IRAS Bot/Corporate Tax → View Corporate Tax Filing Status; Ready to File: clear cache, close active applications, retry. Persistent errors via myTax Mail include date/time, UEN/entity ID/login person, error stage, OS, browser/version, message/screenshot. Old XP/Vista/Firefox 2 examples are not recommended software. A document Submit to Approver/IRAS error may come from multiple portal windows: close all, logout, relogin, reupload.
Review downloads and correcting the wrong attachment
Preparer upload should be downloadable by Approver within a day. If unavailable next day, it may have failed virus scan: delete, scan and have Preparer reupload virus-free. For wrong submitted document, use myTax Mail with submission date, UEN, Approver tax reference, wrong document category and corrected non-fillable PDF within its 2 MB/4 MB limit.
Acknowledgement, correction and technical help
Save successful acknowledgement via top Save as PDF/Print. If absent check Bot/filing status; retrieve within three working days from Notices/Letters → Corporate Tax. Correct a filed return through Corporate Tax → Revise/Object to Assessment, attaching revised tax computation/supporting schedules and following official NOA objection guidance. Browser compatibility is referred to the separate current Technical FAQ; this PDF does not provide a new supported-browser list.
Official source
This article independently explains the substantive contents of the official PDF, including the relevant conditions, procedures and annexes. The linked document remains the authoritative source for its original wording, and later changes should be checked separately.
Read the official PDF ↗