What is the ruling on investing in a company that gives daily profits of 3% for life?

If the aforementioned profit ratio (3%) represents a percentage of the capital, not of the profits, then this condition is void and invalidates the transaction. This is because one of the conditions for the validity of Mudarabah (commenda) or partnership is an agreement on a circulating share of the profit, if any, and it is not permissible to stipulate a fixed amount. This condition alone is sufficient to invalidate and render this type of investment unlawful according to Sharia. As for the phrase "lifetime," it requires clarification.