A temporary enhancement for two loss years
The fifth-edition PDF, published 30 January 2026, describes historical relief for YA 2020 and YA 2021 qualifying deductions. The 2020 Budget extended carry-back from one preceding assessment year to three, and the 2021 Budget extended that enhancement to YA 2021. It is not a general three-year carry-back entitlement for later loss years. Taxpayers could elect either the enhanced three-year system or the ordinary one-year system, with a S$100,000 cap for each loss YA.
Who and what qualify
The source covers companies, sole proprietors and partners including LP/LLP partners, bodies such as clubs/associations, trustees and estate executors carrying on trade, business, profession or vocation. Qualifying deductions are current-year unabsorbed capital allowances (CA) and trade losses, not simply every unused deduction. Brought-forward CA/losses and investment allowances are not eligible in the annex examples. Assessable income means all-source income after applicable CA, losses, approved donations and other relevant deductions; companies also take relevant group relief and investment/M&A allowances into account.
Business continuity and ownership tests
Unabsorbed CA require continuation of the same trade/business/profession when utilised. For companies, the same holders must hold at least 50% at the relevant comparison dates, measured at the company or ultimate-parent level. For CA the first comparison date is the first day of the YA granted; for trade losses it is the first day of the year incurred. The other date is the last day of the preceding YA receiving the deduction. The tests and specific exclusions must be read with sections 6–8 and relevant annexes of the ordinary Carry-back Relief System guide.
Historical comparison dates
For YA 2020 CA, compare 1 January 2020 with 31 December 2017, 2018 or 2019 according to the receiving YA. For YA 2021 CA, compare 1 January 2021 with 31 December 2018, 2019 or 2020. For YA 2020 trade losses, the first date is 1 January 2019; for YA 2021 losses it is 1 January 2020, paired with the same respective receiving-year end dates. Do not substitute the CA dates for the loss dates.
Mandatory order of years and deductions
Enhanced YA 2020 deductions go first to YA 2017, then YA 2018, then YA 2019. Enhanced YA 2021 deductions go to YA 2018, then YA 2019, then YA 2020. Within a receiving year, use current-year unabsorbed CA before current-year trade losses. Unused amounts may be carried forward subject to conditions. Deductions from an earlier loss YA are used before those from a later loss YA; the taxpayer cannot freely rearrange the chronology to maximise a preferred rebate.
Multiple loss years and different income sources
The S$100,000 cap attaches to each loss YA, not to all deductions arriving in a receiving YA. The guide’s combined illustration permits up to S$200,000 against YA 2017, S$300,000 against YA 2018, S$200,000 against YA 2019 and S$100,000 against YA 2020, reflecting overlapping ordinary and enhanced years; each loss-year total still stays within S$100,000. Within income sources, offset the same trade first, other trades next proportionately, then other income sources proportionately.
Concessionary rates and the cap
Where deductions and income belong to different tax-rate categories, apply section 37A adjustment. The cap is measured as A+B: A is deductions against normal-rate income; B is deductions against concessionary-rate income divided by the adjustment factor. That factor is the normal corporate rate divided by the concessionary rate. In the annex’s 17% and 10% categories, the factor is 17/10 and a S$34,000 deduction in the 10% category represents S$20,000 at the normal-rate equivalent. Group relief, personal-relief effects and LP/LLP limitations require the ordinary guide’s detailed scenarios too.
Estimated claims before the loss-year return
An estimated claim could be made after the financial year-end but before filing the loss-year income tax return. Companies submit the election form and relevant preceding-year revised tax computations through myTax Portal Submit Document. Their relevant earlier returns must already be filed; accounts and tax computations are required where earlier Form C was used, but the footnote exempts those documents for earlier Form C-S filings. A nil loss-year ECI must also be filed unless the stated waiver applies: annual revenue not above S$5 million and nil ECI. These are dated YA 2020/2021 procedures.
Estimated claims for other taxpayers
Bodies of persons, trustees and executors submit the prescribed election form and revised computations for the relevant earlier YAs; their earlier returns and original audited/certified accounts must have been submitted. Individuals submit the prescribed form and, where business revenue is at least S$500,000, revised preceding-year computations; earlier returns are required, with certified accounts at that revenue threshold. Enhanced claims require the three relevant earlier YAs where applicable, while ordinary claims concern only the immediately preceding YA.
Actual claims by companies
Companies elect actual deductions no later than filing the loss-year return, indicating the choice in Form C and the tax computation and submitting relevant financial accounts. They cannot use Form C-S to make this election. After e-filing Form C, submit earlier-year revised computations separately through Submit Document using the prescribed revised-computation/loss-carry-back supporting-schedules document category. The required earlier returns, accounts and computations remain subject to the source’s earlier Form C-S document exception. Audit status follows Companies Act exemption conditions.
Actual claims by bodies, trusts, estates and individuals
Bodies of persons, trustees and executors elect by filing the loss-year return, submitting the prescribed form, that return, final loss-year accounts/computations and revised earlier computations. Individuals have a distinct limit: no later than 30 days after service of the loss-year notice of assessment. They submit the form and loss-year return; business revenue of S$500,000 or more also requires loss-year certified accounts/computations and revised earlier computations. The corresponding earlier-year returns/accounts prerequisites continue to apply.
Partnership shares and binding choices
For a partner’s estimated or actual deduction share, the precedent partner must submit certified loss-year accounts/computations showing that share; provisional documents may be used if finalisation is incomplete when elected. For LP/LLP equity partners, also state contributed capital at the accounting period-end. Paragraphs 7.2/7.3 conditions have legal force. Both ordinary and enhanced elections are irrevocable. Consider tax rebates, exemptions and personal relief effects before choosing; the earliest-year ordering may absorb income that would otherwise be sheltered.
The limited 2020 revision exception
A one-time exception allowed an enhanced election made after the 2020 Budget but before 8 May 2020 to be revised to ordinary relief, by covering letter and the required documents for the Comptroller’s consideration. Otherwise IRAS does not accept revised estimated deductions after the election until actual return filing. No second election form is needed with the actual return, but its tax computation must show the actual qualifying deductions. This exception is a closed historical window, not general freedom to switch elections.
Refunds and historical reassessment limits
Subject to the prescribed conditions, the guide states revised assessments and refunds within three months after election submission. Outstanding tax liabilities, including other tax types such as property tax, are deducted from the refund. Excessive carried-back YA 2020 deductions could be reassessed by 31 December 2024, and YA 2021 deductions by 31 December 2025. The example reduces a YA 2020 loss from S$80,000 to S$57,000, revises the loss-year assessment and assesses the S$23,000 excess in receiving YA 2017 by the stated 2024 limit. These are the dates printed for this historical regime.
Annex A: ordinary-rate company deductions
ABC has YA 2020 current CA S$11,000, brought-forward CA S$50,000, rental income S$24,000, current trade loss S$190,000, old losses S$2,000 and investment allowance S$25,000. Only current deductions enter the carry-back: CA S$11,000 and losses S$89,000, reaching S$100,000. Carry CA S$11,000 plus loss S$85,000 to YA 2017 and loss S$4,000 to YA 2018. Remaining old CA S$26,000, combined loss S$103,000 and investment allowance S$25,000 carry forward. YA 2019 already used ordinary CA carry-back S$100,000 against YA 2018 and has no assessable income for further YA 2020 relief.
Annex A: revised tax and rebate effects
YA 2017 originally has S$96,000 after investment allowance; carry-back removes it entirely, so the S$3,867.50 paid after a 50% corporate rebate is discharged. YA 2018 originally has S$90,000 after YA 2019 carry-back. The additional S$4,000 reduces it to S$86,000 and partial exemption falls from S$47,500 to S$45,500. Tax at 17% falls from S$7,225 to S$6,885; after the historical 40% rebate, payable falls from S$4,335 to S$4,131, giving only S$204 relief. The rebates and exemptions here are those of the example years.
Annex B: individual’s allocation
Mr Lim’s YA 2020 CA S$55,000 first absorbs employment S$24,000 and rental S$12,000, leaving qualifying CA S$19,000. With current trade loss S$140,000, his capped carry-back is CA S$19,000 plus loss S$81,000: CA S$19,000/loss S$47,000 to YA 2017, loss S$30,000 to YA 2018 and loss S$4,000 to YA 2019. S$59,000 losses remain forward. The full elected S$100,000 is used before personal reliefs, even where that reduces their benefit.
Annex B: personal reliefs and refunds
YA 2017 offsets trade S$27,000 then employment S$18,000 and rent S$21,000; assessable income becomes nil. Earned-income and self-employed CPF relief become nil, while employee CPF S$3,600 remains in the computation; refund is S$1,414.40 after the historical 20% rebate. YA 2018 offsets trade S$2,000 then employment S$18,000/rent S$10,000; refund is S$28. YA 2019 offsets only S$4,000 of trade S$13,000, leaving trade S$9,000. Self-employed CPF relief becomes 37% × S$9,000 = S$3,330; total personal relief S$7,930 leaves chargeable income S$29,070. Tax S$181.40 less 50% rebate yields S$90.70 instead of S$142, a S$51.30 discharge. The source’s YA 2019 footnote inconsistently prints zero earned income despite its S$18,000 calculation and S$1,000 relief table; the table result is preserved and the inconsistency identified.
Annex C: converting a mixed-rate company’s cap
GHI has YA 2020 available current CA S$34,000 at 10% and S$40,000 at 17%, equivalent to S$20,000+S$40,000=S$60,000 of the cap. Its losses S$17,000 at 10% and S$70,000 at 17% equal S$10,000+S$70,000=S$80,000 normal-rate equivalent. Only S$40,000 cap space remains, so proportional allocation carries S$8,500 actual 10%-category losses and S$35,000 normal-category losses. The latter split S$30,000 to YA 2017 and S$5,000 to YA 2018; S$8,500 concessionary loss goes to YA 2018. Remaining losses are S$8,500 and S$35,000 respectively.
Annex C: earlier-year calculations
YA 2017 first uses concessionary CA S$34,000 against concessionary income S$8,500; surplus S$25,500 converts to S$15,000 at 17%. With normal CA S$40,000 and losses S$30,000, both categories become nil, discharging S$3,825 after the historical 50% rebate. YA 2018 already contains ordinary YA 2019 CA carry-back S$44,348 at 10% and S$73,913 at 17%; its normal-rate cap equivalent is S$100,000. Added YA 2020 losses leave concessionary income S$42,152 and normal income before exemption S$71,087; exemption S$38,044 leaves S$33,043. Tax totals S$9,832.51 and after the 40% rebate becomes S$5,899.51, versus S$6,664.51 previously, refund S$765. YA 2019 itself remains unchanged because it has no assessable income.
Version changes and source enquiries
The May 2020 revision clarified choice between ordinary/enhanced relief and the one-time early-election exception. December 2020 revised company filing procedures, March 2021 added YA 2021 and January 2026 updated renumbered Income Tax Act provisions in sections 4.3/6.4 and Annex C. The new publication date does not reopen the old election windows. Source enquiry numbers are 1800-3568 300 for individuals, 1800-3568 622 for companies, 6351 3883 for bodies of persons and 6351 3363 for trusts/estates; these are the contacts printed in this guide.
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 ↗