SHAFAQNA – The Grand Ayatollah Makarem Shirazi answered a question about investment in non-Islamic banks.
Question: What is the ruling about investment and eaing interest from them in non-Islamic banks?
The Grand Ayatollah Makarem: It is allowed, except when we know that the money is being invested in Haram work like wine making which in this case it is problematic.
Source: PERSIAN SHAFAQNA