Are funds deposited in an Islamic bank—without knowledge of its internal regulations, and designated as a deposit with an unknown annual profit dependent on the bank's earnings—halal or haram?

Whoever wishes to invest their money in an Islamic bank is given a contract that clarifies the nature and conditions of the investment and the rights of both parties. Based on this, the ruling on the transaction and its returns is determined. Returns from contracts permissible by Sharia are permissible, while those from prohibited contracts have details: A contract prohibited in its essence and description, such as interest-bearing loans, its profits are not owned by the capital owner and should be spent on the welfare of Muslims. As for a contract prohibited in its description but not in its essence, such as a فاسدة (corrupt) Mudarabah, all profits belong to the capital owner, and the agent receives a fair wage. Depositing money in an Islamic bank is permissible if the bank adheres to the conditions of a Sharia-compliant Mudarabah, and thus its profits are permissible.