What is Sukuk? Islamic Bonds Explained

Introduction: Understanding Sukuk

Sukuk (singular: sakk) are Islamic financial certificates that represent proportional ownership in an underlying asset, project, or investment activity. Often referred to as "Islamic bonds," sukuk are one of the most important instruments in Islamic capital markets and have grown from a niche product into a significant component of global fixed-income markets.

The comparison to conventional bonds, while useful for orientation, is technically misleading. Conventional bonds represent a debt obligation — the issuer borrows money and pays interest (riba) to bondholders. This structure is impermissible under Shariah law, which prohibits the charging or paying of interest. Sukuk, by contrast, are structured to provide returns to investors through mechanisms rooted in real economic activity — leasing, profit-sharing, or the sale of assets — rather than through interest payments.

This guide explains how sukuk work, the main structural types, the regulatory and Shariah governance frameworks that underpin them, and their growing role in financing infrastructure, sovereign debt, and corporate expansion across the Muslim world and beyond.

How Sukuk Work: The Basic Structure

At its core, every sukuk issuance involves three key elements that distinguish it from conventional debt instruments:

• An underlying tangible asset or economic activity: Unlike conventional bonds, which simply represent a loan, sukuk must be backed by identifiable assets, usufruct (the right to use an asset), services, or a specific business venture. This is the fundamental Shariah requirement — money cannot generate money; returns must be linked to productive economic activity.
• Proportional ownership: Sukuk holders own a proportional share of the underlying asset or venture, not merely a claim to receive interest payments. This ownership interest, however structured, is what generates the return.
• Returns derived from the asset, not from lending: The periodic payments to sukuk holders come from rental income, profit-sharing, or asset sale proceeds — never from interest. The economic effect may appear similar to bond coupon payments, but the legal and Shariah structure is fundamentally different.

A Typical Sukuk Transaction

A simplified sukuk issuance works as follows:

1. The entity seeking financing (the originator) identifies assets — such as real estate, equipment, or infrastructure — that will back the sukuk.
2. A Special Purpose Vehicle (SPV) is established. The originator sells or leases the identified assets to the SPV.
3. The SPV issues sukuk certificates to investors. The proceeds from the sale of certificates flow back to the originator as financing.
4. During the tenor of the sukuk, the originator makes periodic payments to the SPV (e.g., lease rentals), which the SPV distributes to sukuk holders as their return.
5. At maturity, the assets are sold back to the originator (or another buyer), and the proceeds are used to redeem the sukuk certificates at their face value.

This structure ensures that the financing is always anchored in real assets and that returns are generated through permissible commercial activity rather than interest-bearing lending.

Types of Sukuk: The Major Structures

The Accounting and Auditing Organization for Islamic Financial Institutions (AAOIFI), the leading standard-setting body for Islamic finance, has identified 14 permissible sukuk structures. In practice, several structures dominate the global market. Understanding these is essential for anyone involved in Islamic finance or halal investment.

Sukuk al-Ijarah (Lease-Based Sukuk)

Ijarah sukuk are the most widely used and most straightforwardly Shariah-compliant structure. In this arrangement, the originator sells an asset (typically real estate or infrastructure) to the SPV, which then leases it back to the originator. Sukuk holders receive the rental payments as their periodic return, and at maturity, the originator repurchases the asset.

Ijarah sukuk are favoured by Shariah scholars because the return is clearly linked to a tangible asset and the lease payments represent genuine rental income, not disguised interest. The Malaysian government, one of the world's largest sukuk issuers, has used ijarah structures extensively for sovereign sukuk backed by government-owned land and buildings.

Sukuk al-Murabahah (Cost-Plus Sale Sukuk)

Murabahah sukuk are based on a cost-plus sale arrangement. The SPV purchases a commodity or asset at cost and sells it to the originator at a marked-up price, with payment deferred over the sukuk tenor. The profit margin (the markup) provides the return to sukuk holders. This structure is commonly used for short-term corporate financing.

A notable feature of murabahah sukuk is that they are generally not tradeable on secondary markets. Because the underlying transaction becomes a debt obligation once the sale is completed, trading the certificates at a price different from their face value would constitute the sale of debt at a discount or premium, which most scholars consider equivalent to interest. This limits their liquidity and restricts their use primarily to private placements and short-term instruments.

Sukuk al-Musharakah (Partnership Sukuk)

Musharakah sukuk represent ownership interests in a joint venture or partnership. Sukuk holders and the originator contribute capital to a specific business venture, and profits (or losses) are shared according to pre-agreed ratios. This structure is considered by many scholars to embody the ideal of Islamic finance — genuine risk-sharing between investor and entrepreneur.

A variant, diminishing musharakah (musharakah mutanaqisah), involves the originator gradually buying back the sukuk holders' share of the partnership over time, effectively amortising the investors' ownership stake. This structure is used extensively in Islamic property financing and has been adapted for larger sukuk issuances.

Sukuk al-Mudarabah (Profit-Sharing Sukuk)

Mudarabah sukuk are based on a profit-sharing arrangement where sukuk holders provide the capital (rabb al-maal) and the originator provides management expertise and labour (mudarib). Profits are shared according to a pre-agreed ratio, but losses are borne by the capital providers (sukuk holders) unless the loss results from the manager's negligence or misconduct.

Mudarabah sukuk have been used for both corporate and sovereign issuances, though the asymmetric loss allocation can make them less attractive to risk-averse investors compared to ijarah or murabahah structures.

Sukuk al-Wakalah (Agency-Based Sukuk)

Wakalah sukuk have gained popularity in recent years, particularly in the Gulf Cooperation Council (GCC) region. In this structure, sukuk holders appoint an agent (wakeel) — typically the originator — to invest the sukuk proceeds in a diversified portfolio of Shariah-compliant assets or activities. The agent manages the investments and distributes the returns to sukuk holders.

Wakalah sukuk offer greater flexibility than single-asset structures because the underlying portfolio can include a mix of ijarah, murabahah, and other permissible investments. The International Islamic Liquidity Management Corporation (IILM), which issues short-term sukuk for the liquidity management needs of Islamic financial institutions, uses a wakalah structure.

Comparison Table: Key Sukuk Types

Sukuk Type	Underlying Mechanism	Return Source	Tradeable?	Risk Profile
Ijarah	Asset lease	Rental income	Yes	Low-medium
Murabahah	Cost-plus sale	Sale profit margin	Generally no	Low
Musharakah	Joint venture	Profit/loss sharing	Yes	Medium-high
Mudarabah	Investment management	Profit sharing	Yes	Medium-high
Wakalah	Agency investment	Portfolio returns	Yes	Medium

The Global Sukuk Market: Scale and Growth

The global sukuk market has grown substantially over the past two decades. According to data from the Islamic Financial Services Board (IFSB), total sukuk outstanding reached approximately USD 831 billion by the end of 2023, up from under USD 100 billion in 2007. New issuance volumes have fluctuated with market conditions, but the long-term trajectory is firmly upward.

Major Sovereign Issuers

Sovereign sukuk — issued by national governments — account for a significant portion of the market. The largest sovereign issuers include:

• Malaysia: The world's largest sukuk market by outstanding volume. Malaysia's government, central bank (Bank Negara Malaysia), and government-linked entities issue sukuk regularly. The Malaysian capital market benefits from a mature regulatory framework, deep liquidity, and strong Shariah governance infrastructure.
• Saudi Arabia: The Kingdom has become a major sovereign issuer, with the Saudi government using sukuk to fund budget deficits and diversification initiatives under Vision 2030. Saudi sukuk are typically denominated in Saudi riyals for the domestic market and US dollars for international issuance.
• Indonesia: The Indonesian government issues both domestic sukuk (Sukuk Negara) and international US-dollar sukuk. Indonesia has also pioneered retail sukuk products aimed at individual investors, widening access to Islamic capital markets.
• Turkey: Turkey has issued sovereign sukuk (known locally as kira sertifikalari, or lease certificates) in both Turkish lira and foreign currencies since 2012.
• United Kingdom: The UK became the first non-Muslim-majority country to issue a sovereign sukuk in 2014, with a GBP 200 million ijarah sukuk backed by government property. The issuance was heavily oversubscribed, demonstrating appetite for sukuk from both Islamic and conventional investors.

Corporate and Multilateral Issuers

Beyond sovereign issuers, the sukuk market includes corporate issuers, multilateral development banks, and financial institutions. The Islamic Development Bank (IsDB) is a major and regular issuer of sukuk for development financing. Major Islamic banks issue sukuk as part of their capital management, and corporations in sectors from telecommunications to real estate use sukuk as an alternative to conventional bond financing.

Shariah Governance of Sukuk

Every sukuk issuance requires approval from a Shariah supervisory board or committee. This governance layer is what gives sukuk their legitimacy as Islamic financial instruments and is non-negotiable in the structure.

The Role of AAOIFI

AAOIFI, based in Bahrain, has published detailed standards for sukuk (AAOIFI Shariah Standard No. 17) that are widely followed, particularly in the GCC. In 2008, AAOIFI's Shariah board issued a landmark statement expressing concern that many sukuk structures had drifted too close to conventional bonds in practice — particularly those that guaranteed the return of capital to investors regardless of the performance of the underlying asset. This statement led to significant restructuring of sukuk practices and tightened the standards for genuine asset-backing and risk-sharing.

The Securities Commission Malaysia

Malaysia operates its own Shariah advisory framework through the Securities Commission Malaysia and its Shariah Advisory Council (SAC). Malaysian sukuk standards are generally considered more permissive than AAOIFI standards in certain areas, which has occasionally created cross-border acceptance issues between GCC-listed and Malaysian-listed sukuk.

Individual Shariah Boards

Each sukuk issuance typically has its own Shariah advisor or panel that certifies the structure's compliance. A small group of internationally recognised Shariah scholars serve on multiple boards, creating a de facto network of experts whose opinions carry significant market weight.

Sukuk vs Conventional Bonds: Key Differences

Feature	Conventional Bond	Sukuk
Legal nature	Debt obligation	Ownership certificate
Asset backing	Not required	Required (tangible asset or activity)
Returns	Interest (coupon)	Rental, profit share, or sale proceeds
Investor risk	Credit risk of issuer	Asset performance + credit risk
Shariah compliance	Not applicable	Mandatory (Shariah board approval)
Tradability	Freely tradeable	Depends on structure (ijarah yes, murabahah generally no)
Regulatory framework	Securities law	Securities law + Shariah governance

Challenges and Criticisms

Despite their growth, sukuk face several persistent challenges:

• Substance vs form: Critics, including some prominent Islamic scholars, have argued that certain sukuk structures replicate the economic substance of conventional bonds while merely changing the legal form. The 2008 AAOIFI intervention addressed this concern, but the debate continues with each new structural innovation.
• Standardisation: The lack of a single, universally accepted set of Shariah standards for sukuk creates complexity. What is acceptable in Malaysia may face objections in the GCC, and vice versa. This fragmentation increases transaction costs and limits cross-border trading.
• Legal enforceability: Sukuk have been tested in relatively few insolvency or default scenarios. The Dana Gas case in 2017, where the UAE-based energy company attempted to declare its own sukuk non-Shariah-compliant to avoid repayment, exposed uncertainties in how sukuk obligations are treated under conventional legal systems.
• Limited secondary market liquidity: While improving, the secondary market for sukuk remains less liquid than the conventional bond market, partly due to the buy-and-hold behaviour of many Islamic financial institutions and the non-tradability of certain sukuk structures.

Sukuk in the Broader Islamic Finance Ecosystem

Sukuk are one component of a broader Islamic capital markets ecosystem that includes Shariah-compliant equities, Islamic mutual funds, halal fintech platforms, and takaful (Islamic insurance). For businesses in the halal economy, sukuk offer a mechanism for raising capital in compliance with Islamic principles — an important consideration for companies listed in the HalalExpo business directory that operate under Shariah-compliant mandates.

As the global halal economy continues to expand, estimated at over USD 2.8 trillion across food, finance, pharmaceuticals, cosmetics, and travel, the demand for Shariah-compliant financing instruments will grow in parallel. Sukuk are positioned to play an increasingly central role in this expansion, bridging the gap between the capital needs of the halal economy and the ethical investment preferences of Muslim investors worldwide.

Asset-Backed vs Asset-Based Sukuk: The Distinction That Matters Most

One distinction does more to determine a sukuk's real risk than its structural label (ijarah, wakalah, and so on): whether it is asset-backed or asset-based. This sits at the heart of the 2008 AAOIFI debate and is the single most useful thing for an investor to check.

In an asset-backed sukuk, a genuine sale of the assets takes place. Investors have a real ownership claim over the assets, and if the originator fails, their recourse is to those assets. This is true securitisation, and it is what the asset-backing requirement of Islamic finance was meant to deliver.

In an asset-based sukuk — which is the majority of the market — the assets are used to evidence the structure, but there is no true transfer of ownership and no recourse to the assets on default. Investors instead rely on the originator's promise to repurchase the assets at face value, which makes their real exposure the credit of the originator. Economically, that is very close to a conventional unsecured bond, which is exactly what AAOIFI's scholars warned about in 2008 when they flagged that many sukuk guaranteed capital regardless of asset performance.

Neither type is automatically "more halal" — both can be structured compliantly — but they carry very different risk. The 2017 Dana Gas dispute, discussed below, turned on precisely these questions of what investors actually owned.

How Investors Access Sukuk

Sukuk are no longer the preserve of institutions. Routes for individual investors have widened considerably:

• Retail sukuk programmes: Several governments issue sukuk aimed directly at individuals. Indonesia has been a pioneer with its Sukuk Ritel and Sukuk Tabungan savings instruments, and Malaysia has run retail sukuk issuances as well — both lowering minimum investment sizes so ordinary savers can participate.
• Sukuk funds and ETFs: A growing range of Islamic fixed-income funds and exchange-traded funds hold diversified baskets of sukuk, giving investors exposure without having to buy and hold individual certificates to maturity.
• Direct purchase: Larger investors can buy sukuk in the primary market or, for tradeable structures such as ijarah, on the secondary market — bearing in mind that murabahah-type sukuk are generally not tradeable.

For businesses rather than investors, sukuk are a way to raise capital in compliance with Shariah, alongside takaful for protection and Islamic banking for working capital. See the companion sukuk guide for a structural deep-dive.

Frequently Asked Questions

Are sukuk risk-free?

No. Sukuk carry credit risk (the originator may default), market risk (their value moves with rates and conditions), and structure-specific risk — particularly the asset-backed versus asset-based question above, which determines what you can actually claim on default. They are an alternative to conventional bonds, not a substitute for a risk-free asset.

Can non-Muslims invest in sukuk?

Yes. Sukuk are open to all investors, and a large share of demand for sovereign issues — including the UK's 2014 sukuk — has come from conventional institutional investors attracted by the diversification and the asset-linked structure.

How are sukuk rated?

By the same major agencies that rate conventional debt (Moody's, S&P, Fitch), often alongside specialist bodies such as the Islamic International Rating Agency or, in Malaysia, RAM and MARC. A rating speaks to credit risk and says nothing about Shariah compliance, which is certified separately by the issuance's Shariah board.

What's the difference between asset-backed and asset-based sukuk?

In short: asset-backed sukuk give investors a real ownership claim and recourse to the assets if the originator fails; asset-based sukuk do not, leaving investors reliant on the originator's credit and repurchase promise. The full explanation is in the section above — it is the most important risk distinction in the market.

What happens if a sukuk defaults?

Recovery depends on the structure. With a true asset-backed sukuk, holders can look to the underlying assets. With an asset-based sukuk, they rank alongside the originator's other creditors. The 2017 Dana Gas case — where the issuer tried to declare its own sukuk non-compliant to avoid repayment — exposed how untested some of these questions remain under conventional legal systems.

Are sukuk returns fixed like bond coupons?

They can look similar but arise differently. Returns come from rental income, profit shares, or sale proceeds tied to real assets — not from interest. Lease-based (ijarah) sukuk can produce a steady, coupon-like rental stream, while partnership structures (musharakah, mudarabah) share actual profit and loss and are therefore more variable.

Conclusion

Sukuk represent a sophisticated and growing segment of global capital markets that serves both Islamic and ethical investment mandates. Understanding how sukuk work — the asset-backing requirements, the different structural types, the Shariah governance frameworks, and the market dynamics — is essential for anyone involved in Islamic finance, halal industry investment, or cross-border trade in the Muslim world. As regulatory frameworks mature and market infrastructure develops, sukuk will continue to evolve as a viable and important alternative to conventional debt instruments.