Is it permissible to invest money in a company that invests in real estate through a stock system and promotes specified profits, but then it becomes clear that it sometimes borrows from banks? And is it permissible to continue working as an accountant in this company?

Real estate investment, where a company takes shareholders' money to invest it in real estate, and they receive 50% of the profit, is permissible, provided that the company does not guarantee the capital. This constitutes a valid mudarabah (profit-sharing partnership). If there is a profit, the capital owner receives it according to the agreed-upon percentage. If there is a loss, it is borne by the capital, unless there was transgression or negligence on the part of the company. The more preponderant opinion is that stipulating a guarantee of capital does not invalidate the mudarabah, even if the condition itself is invalid.

As for working as an accountant in such a company, if his work is not related to interest-based borrowing in any way, then working there is permissible. However, if his work is related to interest-based borrowing, then it is not permissible to work there, due to the assistance it provides in sin. Indeed, "The Messenger of Allah (peace and blessings be upon him) cursed the one who consumes riba, the one who gives it, its two witnesses, and its scribe, and he said: 'They are all equal (in sin).'"