It's a movie not a book, and needless to say not a completely accurate representation of the world of global banking, but I recommend it as a very good thriller with a certain amount of intellectual interest and some wonderfully filmed sequences including a spectacular 15-minute shoot-out in The Guggenheim. The film treats all banks as criminal conspiracies run by psychopathic maniacs, and presents the system of organised criminality as invincible. I think the reality in a way may be scarier – that indeed we can't control the system, and it can do this to our livelihoods when run by rather ordinary people who have simply lost their moral anchor and an earlier and more prescriptive set of social norms.
For those who are interested, I discussed the movie on Radio 3's marvellous Nightwaves yesterday – the programme is available to listen again for a bit longer & will reappear in the archive later I think. Also on the programme was Romantic Economist Richard Bronk talking about his recent book and a theological discussion about abstinence which extended into whether a bust is a necessary purgative for the economy after a period of boom.
The issue of the requirement of an ethical code is interesting – Ernest Gellner for one asked whether modern industrialism had to have 'iron cage' puritanical ethics to hold its cognitive, economic and political capital together and how rubbery the cage could become before it all stared to come apart. I guess we need to start thinking about this in a bit more earnest now that perhaps the moral compass is well and truly broke!
Daniel Bell posed the same question and obviously himself believed the erosion of the puritan ethic spelled the end of capitalism (and of course, society in general). Recent events as you say have made this issue, raised by the opposing titans of the late 70s, a pretty urgent one. Maybe there's something in all those set texts we middle-aged folks had to read as students?