Question Summary:
Investing in convensional banks

Question Detail:

I would like to know about the legality of the following situations.
 
1)     An individual borrows money. Interest is to be paid on this loan.
I kwon interest is haram. Assuming the rest of the business is aboveboard (sell cement) am I allowed
-         To take a gift from this business
-         Trade with this business
-         Invest in this business
2)Am I allowed to put money in conventional bank without taking interest? If not which banks are the alternative?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
 
According to our understanding of your query, if a person has taken an interest loan for his businesses,  can one accept a gift from him or trade with him or invest in that business.
You are aware that interest haram and the person involved in taking an interest loan has committed a major sin. How ever, if the majority income of the business is halal, then you can take gifts, trade and invest in that business.
 
Abu Ali ad-Dagestani
Student Darul Iftaa
Moscow, Russia
Checked and Approved by,
Mufti Ebrahim Desai