Islamic Windows vs Full Non-Interest Banks in Nigeria (2026)

In most Islamic banking markets, the industry splits between full-fledged Islamic banks and Islamic windows, meaning segregated Shariah-compliant operations inside conventional banks. Nigeria evolved differently: its retail non-interest market today is dominated by six full-fledged licensed banks, and the country's most important window story is about graduation. Understanding the distinction, and Nigeria's version of it, helps you judge any institution claiming halal credentials.

The two models

A full-fledged non-interest bank holds a dedicated CBN licence and its entire balance sheet operates on Islamic contracts: every deposit, every financing, every treasury asset. Jaiz, TAJBank, Lotus, The Alternative Bank and Summit are all this. A window, by contrast, is a conventional bank running a segregated non-interest operation: separate funds, dedicated products, its own Shariah oversight, inside an institution whose main book remains interest-based. The CBN's non-interest framework accommodates window arrangements, and conventional microfinance banks have historically run Shariah-based product windows; academic surveys have named institutions like Kano MFB and Babura MFB among them, though their current window status is unverifiable from public sources as of August 2026.

Nigeria's defining window story: Sterling to AltBank

The best evidence on what windows can and cannot be comes from Nigeria's biggest one. Sterling Bank received approval for a non-interest banking window in January 2014 and ran it for nearly a decade as Sterling Alternative Finance. In July 2023 the CBN granted the business a full standalone licence, and it relaunched that October as The Alternative Bank, a separate institution under Sterling Financial Holdings, with its own audited accounts showing a purely non-interest balance sheet and its own Advisory Committee of Experts publishing signed compliance reports. Notably, its ACE chairman, Shaykh AbdulKader Thomas, had advised the Sterling window since 2013, so the governance continuity is real. The graduation demonstrates both propositions: a well-run window can build a genuine non-interest business (the assets, staff and scholars carried over), and full separation is the destination that removes the structural objections (shared capital, shared treasury, shared brand incentives) that make some customers distrust windows.

Why some savers avoid windows

Three standard objections. Commingling risk: even with segregated pools, the window's capital ultimately belongs to a conventional shareholder whose main business earns interest. Priority risk: in institutional stress, a window is a department, and departments get restructured. Signal risk: a window lets a bank monetise religious demand without committing its balance sheet to the discipline. Against this, window defenders note that segregation rules are real, oversight is scholar-certified, and a window inside a large conventional bank can offer infrastructure a small full-fledged bank cannot. Both positions are legitimate; where you land is a personal judgment. Nigeria's practical answer is that the full-fledged option now exists at scale in every region, so the compromise is rarely necessary.

How to assess any institution claiming halal status

• Licence class first: is it CBN-licensed as a non-interest bank (or non-interest MFB), or is it a conventional institution offering Islamic-labelled products? The licence legally binds the balance sheet; a product label does not.
• Named scholars: a real Advisory Committee of Experts with published members and credentials. All five full non-interest banks name at least their chairman; institutions naming nobody are asking for unearned trust.
• Published evidence: AltBank's signed ACE report inside audited accounts is the market's gold standard. Contract names on product pages (Qard, Mudarabah, Murabaha, Ijarah) are the minimum.
• Balance sheet check: audited accounts showing sukuk, financing assets and commodities rather than an interest loan book. AltBank and Jaiz publish these; newer institutions cannot yet.
• Watch the language: an institution that cannot say which contract governs your deposit has not finished building its product, whatever the brochure says.

The microfinance parallel

The same distinction runs through Nigeria's smallest institutions. Three microfinance banks hold the CBN's dedicated non-interest MFB licence (Tijarah, I-Care, Halal Credit), which legally mandates Shariah compliance and an ACE. Al-Barakah MFB in Lagos, by contrast, has operated on self-described non-interest principles since 2010 under a conventional licence: Islamic by practice and reputation, not by licence class, with no legally required scholar oversight. It is the microfinance version of the window question, and the same verification logic applies: ask which contracts govern your money, in writing.

Frequently asked questions

Are there Islamic windows at Nigeria's big conventional banks today?

The CBN framework permits them, but Nigeria's retail non-interest market is currently served overwhelmingly by the full-fledged banks. The historically significant window, Sterling Alternative Finance, became The Alternative Bank in 2023. If a conventional bank offers you an Islamic-labelled product, apply the assessment checklist above before treating it as equivalent.

Is money in a window really separate?

Under proper window arrangements, deposits sit in segregated non-interest funds that can only finance compliant assets, with dedicated oversight. The separation is structural and real where enforced. Whether it satisfies you personally, given the conventional parent, is the judgment call that drives many savers to full-fledged banks.

Was AltBank's window period less halal than its bank period?

The contracts and scholar oversight were substantially continuous; its ACE chairman served from the window era. What changed in 2023 is verifiability and independence: a standalone licence, separate audited accounts, and a published signed ACE report. Same religion, better paperwork.

Which model is safer for depositors?

NDIC insurance applies either way through the licensed deposit-taking institution. A window rides its parent's full balance sheet, for better or worse; a full-fledged bank stands on its own capital. Neither is categorically safer; assess the specific institution's accounts.

Does HalalWallet recommend windows?

Where a full-fledged alternative exists with comparable service, we default to it: fewer structural caveats, cleaner verification. Where it does not, a well-governed window beats a conventional account. Compare the licensed institutions on our bank accounts page.

How do I verify a window's funds are really segregated?

Ask for the paperwork the framework requires: a window must maintain ring-fenced funds and its own Shariah oversight. Concretely, request the name of the window's Advisory Committee of Experts, its most recent Shariah compliance report, and confirmation in writing that your deposit sits on the segregated non-interest book. A window that can produce all three is operating as designed; one that cannot is a marketing label. The Sterling window that became The Alternative Bank published its governance; that is the standard to hold others to.

Do windows offer the same products as full banks?

Usually a narrower shelf. Windows concentrate on the high-demand basics (current and savings accounts, some financing), while full banks carry domiciliary accounts, term deposits, kids and youth products, business suites and, at TAJBank, retail sukuk access. If your needs go beyond a basic account, the full banks' shelves are simply longer.

Why did Sterling turn its window into a full bank?

Scale and credibility. Sterling Alternative Finance ran as a window from 2014, built a decade of operating history, and converted into the standalone Alternative Bank in July 2023 with its own licence, balance sheet and ACE. The conversion resolved the structural doubts that follow windows (shared balance sheet, conventional parent branding) and the bank now publishes the sector's strongest governance paper. It is the case study for why full licences win trust.

Is a window better than nothing if no full bank operates near me?

Geography matters less than it used to. All four established full non-interest banks run national licences, apps, USSD and cards, so a customer anywhere in Nigeria can bank with them without a nearby branch. A well-governed window with a local branch may still suit cash-heavy customers, after the verification above. The choice is between verified options, not between a window and nothing.