Deducting business expenses in Luxembourg: the guide to avoiding the pitfalls

Managing business expenses well is one of the most powerful — and most legitimate — tax levers in Luxembourg.

Whether you are self-employed, a majority manager or a company director, the quality of your documentation and the consistency of the expenses incurred directly affect the amount of tax due.

Contrary to received wisdom, deduction is not complex: it rests on stable principles, provided they are applied methodically. This article sets out the rules, the most common categories and the pitfalls that cause a deduction to fail during an audit.

I. When does an expense become deductible?

Luxembourg tax law rests on a simple notion: only a cost incurred in the interest of the business can reduce the taxable result. Three conditions must be met:

• a direct link with the business;
• convincing supporting evidence;
• correct accounting treatment.

For a self-employed person, these expenses reduce the profit subject to income tax. In a company, only costs recognised for tax purposes enter into the calculation of corporate income tax and municipal business tax.

It is this requirement of a business purpose that explains why certain expenses, such as fines or private costs, are neutralised.

II. The most frequently admitted expenses

In practice, Luxembourg professionals mainly incur six broad categories of expense, each following a specific logic.

Premises and the home office

Expenses relating to the workplace — rent, energy, internet, maintenance — are admitted where they support the activity. For home working, only the area actually used for professional purposes may be taken into account, on a reasonable and documented pro rata basis.

Business vehicles

Fuel, maintenance, leasing or depreciation: costs relating to a vehicle used for the business are deductible. In the case of mixed use, the business portion must be isolated on the basis of consistent tracking or a prudent estimate.

Equipment and working tools

Computers, phones, software, web hosting, furniture and subscriptions are admitted where they are necessary for the activity. Durable assets are depreciated over several years, whereas current consumables are deducted immediately.

Training and professional dues

Any training intended to maintain or develop skills useful to the activity is deductible, as are dues paid to relevant professional bodies.

Business meals

Meals are allowed where they take place in a business context: client meeting, negotiation, commercial discussion.

To secure the deduction, it is useful to note the client’s name and the purpose of the meeting on the invoice. Private entertainment and manifestly excessive amounts remain excluded.

Fees and insurance

Accountant, lawyer, notary, consultant, professional liability insurance or legal protection: these expenses are among the easiest to justify and are admitted in full.

III. The manager’s status and its impact

The treatment of costs also depends on the manager’s social security status:

• Manager holding more than 25% of the capital: affiliated as self-employed, their social security contributions are deductible in their personal return but not at company level; if the company bears them, they must pass through a shareholder current account.
• Minority manager or non-shareholder manager: covered by employee status, their remuneration and the corresponding employer contributions are fully deductible by the company.

Where several shareholders hold equal stakes, it is the actual decision-making power, rather than the split of capital alone, that serves as the test.

IV. What is never deductible

Some expenses are excluded on principle. The following table contrasts the expenses typically admitted with those systematically rejected.

V. Why rigour changes everything

A well-prepared expense, properly documented and recorded in the right place, is a perfectly legitimate form of tax optimisation. A poorly justified expense, by contrast, may be added back during an audit and directly increase the tax due, sometimes with interest.

Three habits make the difference:

• precise bookkeeping;
• systematic documentation;
• a clear separation between private life and business activity.

Conclusion

Deducting business expenses is neither a privilege nor a grey area: it is a regulated right that rewards method. You still need to know the limits, adapt the treatment to the director’s status and build documentation that will withstand an audit.

At Ease Advisory, we structure your accounts, identify the costs that are genuinely deductible and secure their justification, so that your optimisation holds up on the day the tax authorities look at it. In doubt about a category of expense? Let’s talk.

Need support on this topic? Discover our tax & compliance service in Luxembourg or get in touch with Ease Advisory.