Tax loss carry-forward in Luxembourg: 17 financial years

How does tax loss carry-forward in Luxembourg work?

Tax loss carry-forward in Luxembourg works forward only, and it is now bounded: losses arising from financial years closed after 31 December 2016 may be deducted for seventeen financial years only, whereas losses from financial years closed between 1 January 1991 and 31 December 2016 remain deductible with no time limit at all.

The rule is best read through its mechanism, and it is not a seventeen-year counter running from the loss. For a given tax year, only the losses of the seventeen most recent financial years closed before the start of that tax year are taken into account. The window slides forward by one financial year each year, and the oldest loss drops out of it without notice or formality.

The second point is blunter still: carry-back is not allowed. A company that makes a profit in 2026 and then a loss in 2027 cannot set that loss against the tax already assessed for 2026 and claim a refund. Luxembourg has no carry-back of the kind practised in France or the Netherlands; the loss waits for a future profit, or it serves no purpose.

What conditions does article 114 LIR attach to the deduction?

Article 114 of the Luxembourg income tax law makes the deduction of a carried-forward loss subject to cumulative conditions: regular accounting records kept during the financial year in which the loss arose, a loss that could not be set against other net income in the year it arose, and a loss never deducted in any later tax year.

The first condition is the one most often lost, and it is lost in the past. Accounting quality is assessed in the year the loss appeared, not in the year the taxpayer wants to use it: records reconstructed five years later, without supporting documents or continuity, weaken a stock of losses that had nonetheless sat in the tax balance sheet all along. That is one reason why keeping proper annual accounts for a dormant company is not a negligible formality.

The third condition, in article 114, paragraph 2, number 3, fits in one sentence: only the taxpayer who suffered the loss may deduct it. It applies to corporate income tax and to municipal business tax alike, and it closes the door on any sale, contribution or transfer of a loss stock to a third party. A tax loss is not a transferable asset, however it is presented in a negotiation.

We regularly see, when taking over a file, a stock of carried-forward losses shown as a single line in the tax balance sheet, with no breakdown by year of origin. While carry-forward was unlimited the breakdown carried no stake; since the reform it decides what is still deductible and what is not. Rebuilding that breakdown ten years later, from archived returns and assessment notices, rarely takes less than several days of work.

When will the first losses capped at seventeen years expire?

The first losses hit by the seventeen-year cap in Luxembourg are those of financial year 2017, the first year closed after 31 December 2016: under the sliding-window mechanism, and for a company whose financial year matches the calendar year, they are deducted for the last time in tax year 2034 and then leave the stock for good.

The calculation is worth doing by hand. For tax year 2034, the seventeen most recent financial years closed before 1 January 2034 are the years 2017 to 2033: the 2017 loss is among them. For tax year 2035 the window becomes 2018 to 2034, and 2017 is no longer in it. Nobody notifies the expiry; it is noticed when the stock is next recalculated.

Eight years separate us from that deadline today, which makes it easy to ignore and expensive to discover late. A participation company carrying launch losses from 2017 and 2018, and contemplating a disposal that produces taxable income in 2035 or 2036, will find its stock cut back without anything having changed in its file. The timing of a realisation therefore has to be built around the loss expiry calendar, not after it.

Does a loss-making company still pay tax in Luxembourg?

A loss-making company still owes minimum net wealth tax in Luxembourg: EUR 535.undefined where the balance sheet total does not exceed EUR 350,000, EUR 1,605.undefined up to EUR 2,000,000 and EUR 4,815.undefined above that. The amount is set by reference to the total of the last closing balance sheet, not to the result of the year.

The consequence is direct: no stock of carried-forward losses, however large, removes that minimum charge. A holding company loss-making for five years pays the bracket matching its balance sheet every year, and that is precisely what makes keeping an empty shell alive more expensive than liquidating it. The brackets and the traps for holding structures are set out in our article on minimum net wealth tax.

For municipal business tax the mechanism differs. Operating profit is first reduced by earlier operating losses, provided they were established on the basis of regular accounting records. An allowance then applies: EUR 17,500 for a company subject to corporate income tax, EUR 40,000 for other taxpayers. The tax base is 3 % of the operating profit so adjusted, multiplied by the municipal rate, which brings the aggregate rate to 23.87% in Luxembourg City.

In the ordinary case a loss-making company therefore pays minimum net wealth tax and nothing by way of profit taxes. It still owes its full filing obligations: it is the return that establishes the loss stock and keeps it running, and a year left unfiled is not a neutral year. The scale that applies to profit, once profit returns, is set out in our article on the Luxembourg corporate income tax rate.

What happens to losses on a merger or a company purchase?

The carried-forward losses of an absorbed company are not taken over by the absorbing company in Luxembourg, unless the two companies were previously part of a collective taxation. The principle follows directly from article 114: only the taxpayer who suffered the loss may deduct it, and absorption makes that taxpayer disappear.

The reverse set-off, however, is not prohibited. Nothing stops the absorbing company from deducting its own losses against the positive results of the absorbed activity, which has at times encouraged reverse mergers, where the small loss-making company absorbs the large profitable one and takes over its name. The practice has a name in the administrative doctrine: the sardine swallowing the whale.

The limit is set. Where it appears, from an economic standpoint, that it is the profitable company that in truth absorbed the loss-making one, and the transaction is explained only by the intention to deduct the losses, the administration treats it as an abuse of law that cannot be raised against it. The sanction is refusal of the absorbing company's carry-forward, since economically it is the absorbed one.

The same reasoning applies to buying a dormant company carrying a stock of losses. Taking over a shell to house a new activity, with no continuity with the past activity and for the sole purpose of recovering the carry-forward, is the textbook abuse. The value of a loss stock in a purchase negotiation is therefore discussed in the light of business continuity, never of the amount shown in the tax balance sheet alone.

How does fiscal unity treat losses within a group?

The Luxembourg fiscal unity regime, set out in article 164bis LIR, allows the tax results of the group companies to be pooled and taxed as those of a single taxpayer: the losses of some integrated companies are then set against the profits made by the others, with the parent company liable for the corresponding corporate income tax.

That set-off is confined to losses arising during the unity, however. Losses suffered before the regime applies may be carried forward only if the company that suffered them itself produces a profit, and only up to that profit. They stay locked inside their company of origin, and fiscal unity does not release them.

This boundary governs the order of operations. Integrating a subsidiary that carries pre-unity losses does nothing to speed up their use; what speeds it up is that subsidiary returning to profit. Conversely, integrating a subsidiary before it enters a loss-making cycle allows those future losses to be absorbed at group level, from the very year they arise.

Carried-forward losses and borrowing costs: two separate stocks

A Luxembourg company may carry two tax balances of a different nature, and confusing them distorts any projection: on one side the carried-forward losses of article 114 LIR, on the other the exceeding borrowing costs left undeducted under article 168bis, which caps the deduction of net interest at 30 % of tax EBITDA or at a de minimis threshold of EUR 3,000,000.

The two stocks do not follow the same regime, do not offset each other and are not reported in the same place. The form 500 return has a dedicated schedule for carried-forward borrowing costs and deductible carried-forward borrowing costs, separate from the carried-forward losses line. The article 168bis mechanism is set out in our article on the interest limitation rule.

Good practice fits in one line: keep a single tracking table, by year of origin, for each stock, and reconcile it every year against the assessment notices received. That reconciliation is part of the annual tax file we prepare for a participation company.

Sources and verification

Written for Financial Services Luxembourg and reviewed before publication by Mickaël LOC, licensed accountant (authorisation 10077274). Sources were verified on 29 September 2026, the date on which every period, threshold, amount and legal reference cited here was cross-checked against an official public source.

The sources consulted are as follows. The Luxembourg direct tax administration, for its A to Z page on carry-forward of losses (carry-forward only, carry-back not allowed, losses of financial years closed between 1 January 1991 and 31 December 2016 deductible without time limit, seventeen most recent financial years for years closed after 31 December 2016, cumulative conditions of article 114 LIR), for its page on the calculation of municipal business tax (operating profit reduced by earlier operating losses established on regular accounting, 3 % base, allowance of EUR 17,500 for taxpayers subject to corporate income tax and EUR 40,000 for others) and for its net wealth tax scale page for collective entities (brackets of EUR 535, EUR 1,605 and EUR 4,815 set by reference to the total of the last closing balance sheet). The guichet.public.lu portal, for its pages on the taxable result of a capital company, on the tax impact of a merger (losses of the absorbed company not taken over save for collective taxation, reverse merger amounting to abuse of law) and on the fiscal unity regime (pre-unity losses deductible only against the profit of the company that suffered them). The law of 23 December 2016 enacting the tax reform, which introduced the seventeen-year cap, and the parliamentary papers published by the Chamber of Deputies. Circular of the director of taxes L.I.R. no. 164bis/1 and circular L.I.R. no. 168bis/1, together with the form 500 schedules on carried-forward borrowing costs.

Three points could not be verified against the primary text and are therefore not asserted here. The consolidated wording of article 114 LIR: legilux.public.lu and impotsdirects.public.lu are blocked by the network proxy of our drafting environment, sources were read through indexed extracts using a search restricted to official domains, and one of the wordings so read still presents carry-forward as unlimited in time, a formulation predating the 2016 reform. The literal transposition of the seventeen-year cap to municipal business tax: the pages consulted confirm that earlier operating losses are deductible without restating the period. And the statutory order of set-off between pre-2017 losses, which are unlimited, and later ones, which are capped, which governs how a stock is best used. These three points can be confirmed with the competent tax office, which alone establishes the binding stock in the assessment notice.

This article sets out the state of the law at the date of publication and is not personalised advice: the fate of a loss stock depends on the closing dates of the years concerned, on the quality of the accounting records of each of them, on any restructuring that has taken place and on the company's tax regime. Report an error to contact@financialservices.lu: corrections are dated in the article.