Accounting framework conversion, Lux GAAP, IFRS, foreign GAAP.

Which direction: IFRS to Lux GAAP, or Lux GAAP to IFRS?

The question of direction comes before every other one, and it is the one most enquiries get wrong. The two conversions do not share the same trigger, the same deliverable or the same cost.

Converting into Lux GAAP answers a legal constraint. A Luxembourg company must file statutory annual accounts prepared under Luxembourg accounting standards and presented according to the standard chart of accounts. A subsidiary of a US, British or German group that keeps its operational bookkeeping under the parent's framework therefore has to produce a separate Luxembourg set. This is a compliance obligation: it is not negotiable and it repeats every year.

Converting into IFRS answers a market or group constraint. It is mandatory for the consolidated accounts of companies whose securities are admitted to trading on an EU regulated market. It becomes unavoidable in practice when an institutional investor, an international lender or a potential acquirer requires financial statements comparable to those of its other holdings. This is a credibility obligation, often one-off but heavy in the first year.

Many groups established in Luxembourg live with both permanently: management accounting under IFRS for group reporting, and statutory accounts under Lux GAAP for filing and tax. The real question is then no longer which framework to pick, but how to industrialise the passage from one to the other so that it is not rebuilt from scratch at every close.

Lux GAAP vs IFRS: the differences that actually move the balance sheet

The most visible difference sits on leases. Under Lux GAAP an operating lease stays off balance sheet: rentals go through profit or loss. Under IFRS 16 nearly every lease enters the balance sheet as a right-of-use asset and a lease liability. For a company renting its offices and its vehicle fleet, the balance sheet total can rise sharply and gearing ratios deteriorate mechanically, without a single financing decision having been taken.

The second structural difference sits on goodwill. Under Lux GAAP it is amortised over its useful life, which weighs on profit every year. Under IFRS it is not amortised but tested annually for impairment, which can translate into an abrupt and judgemental charge. The same group therefore shows a smoothed result under one framework and a volatile one under the other.

Deferred tax is the third sensitive item. Lux GAAP recognises it on a limited basis. IFRS requires full recognition on temporary differences between accounting and tax bases, assets as well as liabilities, which brings in line items absent from the Luxembourg accounts and changes opening equity.

Then come the measurement basis, historical cost dominant under Luxembourg GAAP against extensive use of fair value under IFRS; development costs, whose treatment and consequences for dividend distribution differ; provisions, assessed more prudently under Lux GAAP; and revenue recognition, governed by a detailed model under IFRS.

Presentation itself also diverges. Lux GAAP imposes the balance sheet and profit and loss formats of the standard chart of accounts. IFRS sets minimum line items and leaves more latitude. Entities preparing their accounts under IFRS are in fact exempt from the standard chart of accounts, which simplifies their bookkeeping but complicates the return path towards a Luxembourg statutory filing.

The bridge table, core deliverable of a conversion

A conversion is not judged on the set of accounts produced but on the bridge table that comes with it. That document starts from equity and profit under the source framework, lists every restatement line by line with its amount and its justification, and lands on equity and profit under the target framework.

Its purpose is twofold. Towards the approved statutory auditor, it makes the conversion verifiable: every entry ties back to a rule and to supporting evidence, with no grey area to reconstruct in the meeting room. Towards the group, it makes the conversion repeatable: recurring restatements are flagged as such and replayed automatically the following year, leaving only new restatements to be analysed.

A properly built bridge table separates three categories of restatement. Permanent restatements, which will recur at every close as long as the situation lasts, such as lease treatment. One-off restatements tied to a single event, such as an acquisition. And pure presentation reclassifications, with no effect on profit or equity, but indispensable to comply with the standard chart of accounts.

That classification is what determines the cost of the following years. A conversion documented to this standard costs, in year two, a fraction of what it cost in year one. A conversion delivered without a usable bridge table is paid for again in full every year.

Opening balances and comparatives: the real tipping point

Changing framework does not mean flipping a switch on the first day of the financial year. Opening balances have to be restated, which means rebuilding the balance sheet at the transition date under the target framework, and the comparative period has to be restated so that both periods presented rest on the same basis.

That requirement mechanically doubles the scope of the first exercise. A group planning a conversion for the current year in fact has to restate two financial years, plus an opening balance sheet. This is the main cause of overruns on conversion projects, and the point we price first at scoping stage.

The opening balance adjustment is recorded in equity, without passing through profit or loss. That entry is examined closely, because it carries the entire cumulative effect of the change of framework on the company's history. It has to be broken down item by item in the notes.

We recommend treating the opening balance sheet as a standalone deliverable, signed off before the restatement of the year itself begins. Validating the opening position first avoids discovering at the end of the project that an old measurement difference undermines the whole exercise.

Tax consequences of a change of accounting framework

A change of accounting framework is never tax-neutral in Luxembourg, because taxable profit follows the commercial balance sheet. Changing measurement rules means changing the starting point of the tax computation.

Three items concentrate most of the effect. Goodwill amortisation, deductible or not depending on its nature and origin. Deferred tax, which has no tax existence of its own but whose appearance on the balance sheet changes how net assets read. And provision restatements, whose deductibility depends on their purpose and on how certain they are.

That link requires the conversion and the tax return to be handled in the same movement, not sequentially. A conversion carried out without anticipating taxable profit regularly produces an unbudgeted tax charge, discovered at filing time, several months after the year end.

Alongside the accounting bridge table we produce a reconciliation from accounting profit to taxable profit, isolating the conversion restatements that affect the tax base from those that do not. That is the document the tax authorities ask for when they review the transition year.

Can you keep your accounts under IFRS in Luxembourg?

Yes, subject to conditions. The option to apply IFRS as adopted by the European Union was opened in Luxembourg law by the law of 10 December 2010. It is however mandatory, not optional, for the consolidated accounts of companies whose securities are admitted to trading on an EU regulated market, under Regulation (EC) 1606/2002.

Taking the option has practical consequences. Entities preparing their accounts under IFRS are exempt from the standard chart of accounts. In exchange they lose the benefit of the standardised formats, and the filing of their accounts follows arrangements distinct from those applying to Lux GAAP filers.

The decision should be treated as durable. The consistency of methods principle stands against an opportunistic round trip between frameworks, and any change has to be justified and explained in the notes. We check the conditions applying to your situation before the switch rather than after it.

In most of the cases we handle, the optimal answer is not to choose a framework but to run both cleanly: statutory bookkeeping under LuxGAAP as the single source of truth for filing and tax, and a documented, replayable set of IFRS restatements for group reporting. That configuration connects directly with consolidation and with the Lux GAAP framework itself.