Buying shares allowed but what when the deal with interest?

[new2010]

Assalamalaikum,

my bank sent me a offer to open a share account for stock market. Interesting part on this is it is for free to open, however you have to pay something if you want to deal with shares. I think this one goes to the provider who manages all the shares. My question is: Is it haram to open such a account? I read a fatawa that it is permissible to deal with shares when the company of whom you have bought shares deals with haram, like alcohol etc, but what me makes some headache is banks deal with riba, or do they in that case not?

I need an answer until the next insha´Allah, because offer will expire then. Jazak Allahu Khairan.