Luxembourg IP Box: The 6.75% Tax Regime for Patents

What is the Luxembourg IP Box?

The IP Box (intellectual property regime) is a tax mechanism that partially exempts income from the exploitation of intellectual property rights. Legal framework: article 50ter of the Luxembourg Income Tax Law (LIR), introduced in 2018 to replace the previous regime (article 50bis). The new regime complies with the modified nexus approach defined by Action 5 of the OECD BEPS plan, which requires a substantial link between exempt income and R&D activities actually carried out.

In practice: 80% of qualifying net income is exempt from both IRC and ICC (and from wealth tax). With a theoretical aggregate rate of 24.94% in Luxembourg City, the effective rate on qualifying IP income becomes 24.94% x 20% = 4.99%, to which the minimum wealth tax is added, resulting in a typical effective rate of around 5 to 6%.

Intellectual property eligible for the regime

The list of eligible IP assets is exhaustive. The following are eligible:

• Registered patents and utility models
• Software protected by copyright (article L.111-1 of the Luxembourg Intellectual Property Code)
• Plant variety certificates
• Orphan drugs and supplementary protection certificates (SPC)
• Plant variety designations and certificate extensions

The following are explicitly excluded: trademarks, designs, goodwill rights, unpatented trade secrets, ordinary databases and, more broadly, any marketing-related IP asset. This deliberate exclusion distinguishes the Luxembourg IP Box from older, more permissive regimes and brings it into line with OECD standards.

Qualifying and non-qualifying income

Income covered by the regime includes:

• License royalties received for the use of a patent, software or other eligible asset
• Royalties embedded in the sales price of a product or service incorporating the IP (allocated portion based on a justifiable method)
• Capital gains realised on the disposal of the IP asset
• Compensation received in infringement proceedings

Income must be net: development, operating and amortisation costs of the asset are deducted before the 80% exemption is applied.

The nexus formula: the core of the regime

Not all IP income is automatically exempt. A ratio known as the nexus ratio adjusts the percentage of net income that actually benefits from the exemption:

Nexus ratio = (qualifying R&D expenditure x 130%) / (total R&D expenditure)

Three key points:

• Qualifying expenditure: costs incurred directly by the Luxembourg taxpayer OR outsourced to unrelated parties (university, external laboratory, independent freelancer).
• Non-qualifying expenditure: intra-group outsourcing (R&D outsourced to a subsidiary or sister company) AND acquisition costs of pre-existing IP assets.
• 30% uplift (x130%): a premium granted to partially offset the disadvantage of groups that cannot avoid intra-group outsourcing.
• Cap: the nexus ratio can never exceed 100%, even if the formula would mathematically allow it.

Practical calculation example

A Luxembourg SARL develops a SaaS software product and earns 1,000,000 euros in license income during the financial year. It has incurred 600,000 euros of total R&D expenditure, of which:

• 400,000 euros in salaries of Luxembourg developers (qualifying)
• 80,000 euros for services from an independent external laboratory (qualifying)
• 120,000 euros of R&D outsourced to an Irish subsidiary (non-qualifying)

Qualifying expenditure: 480,000 euros. Nexus ratio = (480,000 x 130%) / 600,000 = 624,000 / 600,000 = 1.04, capped at 100%. Qualifying net income (assume 700,000 euros after allocation of costs): 80% exemption, so 560,000 euros exempt, 140,000 euros taxed at 24.94% = 34,916 euros. Effective rate on IP income: 4.99%.

Substance requirements in Luxembourg

For income to qualify as Luxembourg IP, the company must demonstrate substantial R&D activity on Luxembourg territory:

• Qualified R&D team employed in Luxembourg (local permanent contracts, affiliated with CCSS)
• Workspaces, laboratories or development environments physically located in the Grand Duchy
• Technical documentation of R&D work (timesheets, lab notebooks, git history, specifications, tests)
• Strategic decisions regarding IP (patent filings, licensing strategy, open source policy) taken from Luxembourg
• Assignment or license agreements executed under Luxembourg or EU law

The Administration des Contributions Directes (ACD, Luxembourg's direct tax authority) may require proof of these elements during a tax audit. A mailbox-style structure that merely holds the IP without real activity risks an outright denial of the IP Box with retroactive reassessment over 5 to 10 years.

Mandatory documentation

To benefit from the IP Box, the company must maintain per-asset, per-year documentation including:

• Precise identification of each IP asset (patent number, software title, copyright registration)
• Breakdown of income per asset and per type (license, embedded royalty, capital gain)
• Breakdown of qualifying / non-qualifying R&D expenditure per asset
• Calculation of the nexus ratio and qualifying net income for the year
• Justification of allocation methods (sales of products incorporating the IP)

This documentation must be available on request and kept for at least 10 years. A simple declaration in the 500 return is not enough.

Advance tax ruling: recommended

A ruling request (advance tax ruling) with the ACD allows for upfront validation of the IP Box structure's tax treatment. Processing time: 3 to 6 months. Cost: fixed fee of 3,000 to 10,000 euros depending on complexity. Validity: 5 years, renewable. The ruling is not mandatory but strongly recommended for high-stakes files because it provides legal certainty and avoids subsequent challenges. It is crucial to submit a complete and honest file: any omission or inaccuracy on a material element may void the ruling retroactively.

Sectors that benefit most

• SaaS software publishers: source code protected by copyright, recurring license revenues, local dev team.
• Biotech and pharma: patents on molecules, processes and medical devices, SPC on medicines.
• Deeptech and industrials: patents on manufacturing processes, materials, patentable algorithms.
• Agritech: plant variety certificates, biotech patents.

Pure content plays (media, music, brand) are not eligible: their assets fall outside the scope defined by article 50ter LIR.

Common pitfalls and mistakes

• Outsourcing R&D to the parent company: caps the nexus ratio and drastically reduces the effective exemption.
• Buying IP rather than developing it: non-qualifying acquisition costs, resulting in a very low nexus ratio.
• Insufficient substance: fragmented man-hours, no tech lead in Luxembourg, vague outsourcing invoices.
• Incorrect allocation for complex products: overestimating the IP share in the sales price of a product or service to maximise the exemption exposes the company to a reassessment.
• Pillar 2 oversight: for groups exceeding 750 million euros in consolidated turnover, the IP Box exemption may trigger a top-up tax to reach 15%.

Comparison with neighbouring regimes

The Netherlands (Innovation Box), the United Kingdom (Patent Box), Belgium (Innovation Deduction) and Ireland (Knowledge Development Box) offer comparable regimes. The Luxembourg IP Box stands out with:

• An effective rate aligned with benchmarks (5% vs. 6.25% in the Netherlands, 10% in the UK, 6.25% in Ireland)
• Clear inclusion of copyright-protected software (not all regimes do this)
• A pragmatic administration and a track record of stable rulings
• Possible combination with the SOPARFI regime upstream (holding) and tax treaties for outbound flows

For the complementary framework on international flows, see 83 conventions fiscales : Double imposition Luxembourg. For the corporate base tax, see Taux d'imposition des sociétés au Luxembourg en 2026.

Conclusion: powerful but demanding

The Luxembourg IP Box is one of Europe's most effective tax optimisation tools for innovative companies that create and exploit their IP locally. But it does not come for free: it requires genuine R&D in Luxembourg, rigorous documentation, controlled qualifying costs, and ideally an advance ruling. Rushed structures without substance face a very significant risk of reassessment. When properly prepared, the regime saves 20 percentage points of tax per year and can represent several million euros in gains over time for a growing SaaS publisher.