Question:
Can one own bank shares in chuts laarets where a majority of customers are non-Jews
Answer:
The fact that most customers are non-Jews is not really the issue here, because if when the bank lends money and collect interest from the Jew, it is ribbis. The question though is, is owning shares in a bank considered like you are a real owner of the bank or is it considered that you only invested money in the sense that you can gain from the company financially. This question comes up in regard to a number of issues. Can one own shares in a company that sells chometz, or non-kosher products, or that sells chometz products on Pesach? There is controversy regarding this, and several poskim are lenient about this, except if the person has a significant number of shares, and his opinion can make a change in the running of the company. The custom is to be lenient about this, (otherwise a person would not be allowed to open a bank account and get interest from it, or pay interest to it, because there are Jewish shareholders, that are now paying ribbis). See the following link https://dinonline.org/2020/03/08/owning-stock-in-traife-companies/
