Usury (Interest) in Judaism

I was reading those 613 laws of Judaism. One topic that really fascinates me is economics and business, so I scrolled down to that part and found this:

171. Not to make a loan to an Israelite on interest (Lev. 25:37) (CCN54).
172. Not to borrow on interest (Deut. 23:20) (because this would cause the lender to sin) (CCN55).
173. Not to take part in any usurious transaction between borrower and lender, neither as a surety, nor as a witness, nor as a writer of the bond for them (Ex. 22:24) (CCN53).

This is a subject I am probably ignorant in and would like someone to share their knowledge with me.

First (I dont want to sound racist, or offend anyone), but I hear alot of people saying things like "The Jews practise usury" and make it sound like it is permissible under Jewish law...is this just a giant misconception?

Second, as a business student, I keep my eyes open for different firms in consulting, real-estate and especially investment management. Something that I have noticed is that a lot of these Investment Management firms (at least the ones I have seen) are partnerships where the partners are most likely to be Jews. Now, we all know that in the West, Interest (usury) is a central pillar in the economic system...which undoubtly means that these Jewish owned Investment firms are practising Usury. Is this permissible? Why, or why not? And if it isn't permissible, do these Jews do it out of ignorance or do they base their actions on different laws/opinions/interpretations?

Anyone that could answer these for me will have my Thanks! And sorry again if I sound ignorant, but I genuinely would like to know.