An Islamic bank investment account is money entrusted to a Sharia-compliant bank, which deploys it in permissible assets and pays the holder a share of the profits earned, with no interest fixed in advance and a possible loss of capital.
A holder who shares in results rather than a creditor
On a current account the bank must repay everything. On an investment account the customer supplies funds that the bank puts to work: the holder owns not a guaranteed claim but a right to the pool's profits, so the return involves no riba.
Where the money goes: the pool of financed assets
The bank gathers holders' money into a pool invested in Murabaha, Ijara or Musharaka financing granted to households and companies. It often adds its own capital to the pool, which obliges it to split the result in proportion to the amounts each side has committed.
From gross profit to the distributed rate
Each month the bank calculates the pool's net income, allocates the share earned by its own funds, then applies the contractual ratio, for example 60 percent to holders and 40 percent to the bank as manager. The quoted rate is therefore observed afterwards, never promised.
The reserves that smooth returns
To avoid erratic returns, many banks build a profit equalisation reserve, deducted before profits are shared, and an investment risk reserve, deducted from the holders' portion. The rules for funding and releasing both reserves should appear clearly in the account terms.
Unrestricted or restricted account: what changes for the customer?
With an unrestricted account the holder lets the bank choose how to deploy funds across its permissible activities. With a restricted account the holder sets limits such as a sector, a contract type or a specific project. The latter offers more control but concentrates risk.
Restricted accounts managed off balance sheet
When the holder imposes conditions, the bank often acts purely as manager and records these funds off its balance sheet. The underlying assets stay identifiable, which eases Sharia review but rules out pooling them with the institution's other investments.
Displaced commercial risk, a tension specific to Islamic banks
If the pool earns less than market rates, holders may withdraw their money. To keep them, the bank sometimes gives up part of its mudarib share, absorbing a risk that legally belonged to the investors. Supervisors watch this practice closely.
Capital and the IFSB alpha factor
IFSB prudential standards allow supervisors to treat only a fraction of the assets funded by these accounts as requiring cover from the bank's own capital. This alpha factor reflects the share of risk that the institution actually bears in practice.
What UK deposit law changes
In the United Kingdom, a product classed as a deposit must be repayable in full. Islamic banks there mainly offer expected-profit accounts whose documentation provides the capital protection the regulator requires, while a true loss-sharing account falls under a separate investment regime.
The Bank of England Alternative Liquidity Facility
Since December 2021, Islamic banks based in the United Kingdom can place liquidity with the Bank of England through a non-interest facility backed by high-quality sukuk. The return on those securities, net of costs, replaces conventional remuneration for participants.
Clauses to read before signing
Look for the sharing ratio, distribution frequency, withdrawal conditions, reserve deductions and the treatment of losses. Ask for the history of distributed rates and for the fatwa or opinion of the Sharia board that approved the account structure.
How tax authorities treat the profit received
In several countries the tax authority treats profit paid on these accounts like interest income. In the United Kingdom, the alternative finance rules align their taxation in this way. Holders should therefore declare these sums as ordinary investment income.
Specialist external source
The Bank of England site describes its sukuk-backed Alternative Liquidity Facility, which lets UK Islamic banks hold liquidity at the central bank without earning interest.