[mruts]

The latter. Like everything else in finance, you have to learn on the job. The good news is that since no one who hasn't worked on Wall St (and even most who have) knows anything about the industry (and that the talent pool is pretty small compared to Silicon Valley, at least for non shit-analyst jobs), they are willing to accept people who don't know much, providing you have the basic chops (basic calculus, statistics, and good programming skills).

I really wish more programmers would get into the industry, since the status quo is pretty terrible. The financial industry needs more quantitative folks so we can kill off the dinosaurs of the "greed is good"/pre-decimalization world :)