Jake Bernstein’s Secrecy World has been sitting on my to-be-read list for quite some time now; it’s specifically about the Panama Papers and what they tell us about the world of global finance. Can’t offer a review, since I haven’t read it, and it may well be lib-brained, but it’s definitely about the topic you’re interested in.
I said it back then and I stand by it now: they should have just held everyone back a year.