What is the ruling on dealing with a company that offers a financial gift for the purchase of unknown shares, and then undertakes to invest them on behalf of the buyer?

The question requires further clarification. Generally, ignorance (jahalah) is not permissible in contracts of exchange. However, in the case of gifts and presents, ignorance does not invalidate them, according to the more correct opinion, as mentioned by Ibn Uthaymeen. So, if the company gives an unknown gift without recompense and then invests it for the person, there is no harm in that. If the matter is otherwise, please clarify it.