Is investing in investment funds - especially those issued by Islamic banks that avoid investing in companies whose legitimacy is doubtful - permissible or forbidden?

Investing in the stock market is permissible if the investor adheres to Sharia guidelines, and there is no difference between speculating personally or by authorizing another party who abides by the guidelines.

Nevertheless, investing in the stock market is generally not recommended due to the abundance of prohibited transactions therein, such as margin buying and short selling, and the difficulty of avoiding them.

However, if it is possible to avoid the prohibitions, the basic principle is permissibility. Therefore, the questioner must verify that the bank adheres to Sharia rulings in its speculation with Sukuk. If this is confirmed, then there is no objection to purchasing the Sukuk; otherwise, it is not permissible.