Islamic banking in the Gulf
Who certifies a product as compliant, why the answer differs by country, and what an "Islamic window" is.
Who certifies what
Every Islamic bank has its own sharia supervisory board, which approves a product before launch and audits it afterwards. Above the bank, some jurisdictions add a central authority whose rulings bind everyone: the UAE has the Higher Shari'ah Authority at the central bank, Bahrain requires AAOIFI's standards of its Islamic licensees, and Oman regulates the sector through a published framework rather than leaving it to each bank. Saudi Arabia has historically left certification to the boards at the banks themselves.
The consequence is worth stating plainly: "sharia-compliant" is not one standard across the region. A structure approved in one country can be refused in another, and two products sharing a name can rest on different contracts. Where it matters, the document to read is the bank's own fatwa and contract, not the brochure.
Full banks and windows
A fully Islamic bank runs its whole balance sheet on these contracts. An "Islamic window" is a separate operation inside a conventional bank, required to keep segregated funds and its own accounts. Windows are permitted in the UAE, Bahrain and Oman; Qatar ordered conventional banks to close theirs in 2011, on the reasoning that separation inside one institution is difficult to guarantee.
The standing criticism of windows is exactly that: the funds are declared separate, but the capital, the treasury and the risk appetite belong to a conventional parent. Those who accept them argue that segregation is auditable and that windows widened access considerably. Both positions are held by serious people.