Luxembourg infrastructure debt fund: why managers use RAIF, SIF and ELTIF structures

Luxembourg has become the default home for European infrastructure debt funds. For managers lending into energy transition, digital infrastructure, transport, or social assets across the EU, the Grand Duchy offers a flexible toolbox of investment vehicles, strong investor protection, and a mature ecosystem for private credit and infrastructure strategies.

This guide explains how infrastructure debt funds for Europe are structured in Luxembourg, which fund regimes are typically used, and how real-life managers apply these tools in practice.

Key features and benefits of Luxembourg infrastructure debt funds

• European reach: once managed by an EU AIFM, a Luxembourg infrastructure debt fund can be marketed to professional investors across the EU under AIFMD.
• Flexible structuring: sponsors can combine RAIFs, SIFs, ELTIFs, and partnerships with SPVs to tailor governance, tax, and risk allocation.
• Real-asset-backed yields: investors gain exposure to loans secured on core infrastructure such as renewables, transport, and digital networks.
• Institutional-grade governance: AIFMD risk controls, depositary oversight, and independent valuation support long-term capital.
• Scalability: umbrella funds with multiple compartments allow managers to run several strategies from a single Luxembourg platform.
• Regulatory clarity: AIFMD II and local guidance provide a clear framework for loan-originating AIFs and illiquid assets.

Why Luxembourg for European infrastructure debt?

Luxembourg is now one of the leading global hubs for debt funds. Total assets under management of debt funds in Luxembourg reached around EUR 510 billion by the end of 2023, with growth of more than 20% in just six months. Separate estimates place private debt held by Luxembourg funds at well over USD 400 billion in 2024. This critical mass has made Luxembourg the go-to jurisdiction for European infrastructure debt platforms.

For European infrastructure debt managers, Luxembourg offers:

• EU passporting through AIFMD: once the fund has an EU AIFM, it can be marketed to professional investors across the EU.
• Flexible legal toolbox: specialised regimes for alternative strategies, including credit, infrastructure, and private debt.
• Tax-efficient cross-border structuring: often via partnerships or corporate funds combined with SPVs for lending and security.
• Deep service ecosystem: AIFMs, depositaries, administrators, and law firms with long experience in infrastructure and private credit.
• Alignment with AIFMD II: a framework that explicitly recognises loan-originating AIFs and channels more capital into the real economy.

Within that ecosystem, several Luxembourg fund regimes are particularly suited for infrastructure debt funds with a European focus.

Core Luxembourg fund regimes for infrastructure debt

Most European infrastructure debt funds in Luxembourg are structured as alternative investment funds (AIFs), not UCITS. The main options are:

• RAIF – Reserved Alternative Investment Fund
• SIF – Specialised Investment Fund
• Part II UCIs – non-UCITS regulated funds
• ELTIF – European Long-Term Investment Fund
• Unregulated partnerships – SCS / SCSp combined with an external AIFM

Surveys of the Luxembourg debt fund market show that RAIFs account for the majority of vehicles, followed by SIFs, with Part II funds and other regimes making up the balance. Infrastructure debt funds broadly follow the same pattern, with a strong bias toward RAIF and SIF structures.

The following sections look at each regime through the lens of an Infrastructure Debt Fund Europe strategy.

RAIF: the workhorse for European infrastructure debt funds

The Reserved Alternative Investment Fund (RAIF) can invest in all types of assets, including infrastructure loans, project bonds, private placements, and structured debt. The RAIF itself is not authorised directly by the CSSF but must always appoint an authorised external AIFM.

Key features for infrastructure debt:

• Speed to market: the product is not supervised directly, only the AIFM is, which allows relatively fast launches or new compartments.
• Professional / well-informed investor focus: ideal for institutional allocators, insurers, and pension funds that dominate infrastructure debt allocations.
• Multi-compartment design: one RAIF umbrella can host several sub-funds (for example, Core Infrastructure Debt Europe, Green Energy Debt, Digital Infrastructure Mezzanine), each with its own strategy and investors.
• Flexible legal forms: can be formed as a partnership (SCSp/SCS), a corporate SICAV, or an FCP (common fund) depending on tax and governance preferences.

For infrastructure debt, RAIFs are typically structured as SCSp (special limited partnership) or SICAV-RAIF, with:

• A Luxembourg AIFM (or another EU AIFM) managing the fund.
• One or several Luxembourg SPVs used to originate loans and hold security packages.

This combination gives managers the flexibility of a partnership (capital accounts, carried interest mechanics) with the marketing power of the AIFMD passport.

SIF: regulated infrastructure debt platforms

The Specialised Investment Fund (SIF) is a more traditional regulated AIF product. Like RAIFs, SIFs can invest in a wide range of assets and are typically open only to well-informed investors. Unlike RAIFs, SIFs are authorised and supervised by the CSSF.

For infrastructure debt:

• The SIF is directly authorised and supervised by the CSSF.
• It must comply with a risk-spreading requirement, such as limits on exposure to a single issuer.
• It can be structured as an umbrella with multiple compartments dedicated to different risk/return profiles (for example, senior infrastructure debt versus subordinated or mezzanine tranches).

Recent legislative updates have modernised the SIF regime, aligning it with evolving market practice and the broader Luxembourg alternative investment toolbox. For European infrastructure debt managers seeking a fully regulated product with strong CSSF oversight to reassure conservative institutional investors, a SIF remains a premium option.

Part II UCIs: when broader distribution is needed

Part II funds are non-UCITS regulated funds that can be marketed to a wider investor base, including retail in some cases, subject to local rules. They are less common than RAIFs and SIFs in the private debt and infrastructure debt space but are sometimes used when:

• The sponsor wants to target semi-professional or high-net-worth investors in addition to institutions.
• The strategy remains illiquid and alternative, but the distribution footprint should be closer to that of traditional funds.

In the Luxembourg debt fund universe, Part II funds represent a smaller share of vehicles, but they can be strategically relevant where national private banking networks want an on-platform infrastructure debt exposure under a regulated Luxembourg label.

ELTIF: infrastructure debt for long-term and increasingly retail capital

The European Long-Term Investment Fund (ELTIF) label has become a powerful tool for infrastructure and private debt vehicles with a long-term horizon. Luxembourg is the dominant domicile for ELTIFs, and many of them focus on infrastructure and real assets.

ELTIFs can invest in:

• Infrastructure projects and companies.
• Private debt and loans.
• Real assets and long-term projects.

ELTIFs are particularly relevant when:

• The infrastructure debt strategy has a 10+ year horizon and is genuinely long term.
• The sponsor wants to access wider European distribution, including eligible retail investors, under a harmonised EU label.

In practice, many Luxembourg ELTIFs combine a RAIF or SIF legal structure with an ELTIF label, offering infrastructure or private debt exposures across Europe to a broad investor base.

Unregulated partnerships with AIFM: SCS / SCSp for club deals and mandates

Beyond regulated funds, infrastructure managers also use unregulated Luxembourg partnerships, notably SCS (common limited partnership) and SCSp (special limited partnership). When these partnerships qualify as AIFs and appoint an AIFM, they can access the AIFMD passport while avoiding product-level supervision.

This model is attractive for:

• Club-style European infrastructure debt funds with a limited number of large institutions.
• Separately managed accounts or bespoke mandates for a single insurer or pension fund.
• Opportunistic, higher-yield strategies where speed and structuring flexibility matter more than retail-style branding.

Concrete European examples of infrastructure debt strategies using Luxembourg

European Infrastructure Debt (Lux) – Goldman Sachs Asset Management

Goldman Sachs Asset Management runs a Luxembourg-domiciled infrastructure debt strategy targeting European opportunities. A typical structure uses a Luxembourg umbrella fund with one or more infrastructure debt compartments, investing in senior secured loans or private placements to European infrastructure companies in renewables, transport, and utilities.

Loans and security interests are often held through Luxembourg SPVs, depending on the jurisdiction and regulatory specifics of each borrower.

Macquarie European Infrastructure Debt Fund (MEID)

Macquarie Asset Management has raised several billion euros for its European infrastructure debt initiatives, including Macquarie European Infrastructure Debt Fund (MEID), a dedicated European infrastructure debt fund. Luxembourg is commonly used as a hub for pan-European infrastructure lending platforms run by large managers.

A typical Luxembourg-centric setup for such a manager includes:

• A Luxembourg RAIF or SIF as the main fund.
• Luxembourg and, where relevant, local SPVs to originate loans into renewable portfolios, toll roads, ports, or fibre networks.
• Co-investment feeders for specific institutional investors.

Luxembourg ELTIFs focusing on infrastructure and private debt

With Luxembourg hosting a large share of European ELTIFs, a significant portion of these vehicles invest in infrastructure, private equity, and private debt, often combining equity and debt investments in European infrastructure assets.

Recurring themes include:

• Infrastructure ELTIFs providing senior or mezzanine debt to renewable energy portfolios in Spain, Italy, or the Nordics.
• Social infrastructure debt funds financing hospitals, care homes, or educational facilities, combining project-finance style loans with long-tenor capital.
• Digital infrastructure debt strategies lending to data centres, telecom towers, and fibre networks across several EU jurisdictions from a single Luxembourg platform.

Key regulatory considerations for Luxembourg infrastructure debt funds

• AIFM and AIFMD / AIFMD II

An Infrastructure Debt Fund Europe structured in Luxembourg will almost always qualify as an AIF managed by an authorised EU AIFM. AIFMD and AIFMD II clarify the rules for loan-originating AIFs, including leverage caps, risk management, and retention requirements, and they allow managers to originate loans across the EU under the AIFM passport.

• CSSF guidance on illiquid assets and depositaries

The CSSF requires Luxembourg depositaries to perform ex-ante controls before acquiring illiquid assets, which is highly relevant for infrastructure and private debt strategies. This includes verification of ownership and collateral for infrastructure loans, monitoring of cash flows and covenants, and oversight of valuation and asset eligibility.

• Marketing rules and cross-border distribution

The CSSF maintains specific rules and guidance on marketing AIFs in Luxembourg, aligned with the EU Cross-Border Distribution of Funds (CBDF) Regulation. For an Infrastructure Debt Fund Europe, this framework enables efficient passporting to professional investors across the EU, use of local private placement regimes for non-EU markets where relevant, and clear documentation of pre-marketing versus marketing activities.

How to set up a Luxembourg infrastructure debt fund for Europe

Damalion experts guide you to setup your Luxembourg infrastructure debt fund in a streamline way:

– Define your infrastructure debt strategy:
Clarify target sectors, geographies, risk level (senior, mezzanine, or hybrid), expected fund size, and investor profile.

– Choose the right Luxembourg fund vehicle:
Select between RAIF, SIF, Part II UCI, ELTIF, or an unregulated partnership structure based on regulation, speed to market, and distribution objectives.

– Appoint an AIFM and key service providers:
Engage an authorised AIFM, administrator, depositary, auditor, and legal counsel with experience in infrastructure debt.

– Design the SPV and lending structure:
Set up Luxembourg and, where needed, local SPVs to originate loans, hold security, and manage cash flows from infrastructure assets.

– Prepare documentation and regulatory filings:
Draft the fund documentation, negotiate service agreements, and coordinate any required CSSF notifications or approvals via the AIFM.

– Launch the fund and onboard investors:
-capital commitments, complete KYC and AML checks, close initial subscriptions, and start originating or acquiring infrastructure debt assets.

Investor profiles and strategy design

Investor demand for European infrastructure debt is driven by pension funds, insurance companies, sovereign entities, banks, and sophisticated family offices seeking yield and duration. Luxembourg’s platform allows managers to align strategy design with this demand, from core senior loans to higher-yielding subordinated tranches and thematic strategies focused on energy transition, digital infrastructure, or social assets.

Takeaways for investors and sponsors

For investors, a Luxembourg infrastructure debt fund focused on Europe offers:

• Access to diversified portfolios of infrastructure loans and private placements across jurisdictions and sectors.
• Structures supported by AIFMD governance, potential CSSF oversight (for SIF, Part II, ELTIF), and robust depositary controls over illiquid assets.
• A range of risk/return profiles, from core senior secured strategies to higher-yield subordinated debt.

For sponsors and managers, Luxembourg provides:

• A scalable toolbox where RAIF and SIF dominate the market, with ELTIF as a strong option for long-term and, in some cases, semi-retail capital.
• Tax-efficient partnership structures (often SCSp) with clear carried interest and co-investment frameworks.
• A proven environment for European cross-border infrastructure lending, with the ability to plug in local origination teams and SPVs.

Frequently asked questions about Luxembourg infrastructure debt funds