I don't have the slightest idea since I don't work there. I was more wondering if there was anything I would need to know before applying specific to the industry or if it's just like any other software engineering job.
To succeed in financial dev you need to be comfortable working in a heavyweight, slow large-corporate environment. Think lots of meetings, lots of time estimation & metrics, using Java, C# or C++ (shudder), people caring what you wear. If you can deal with this, the rewards are great. If you can't, it's hell.
There are finance startups where the above doesn't apply, but they don't pay like the banks do.
What you describe in the first paragraph aren't roles that pay 400k...
Math... and a lot of it. Look up job descriptions for a Quantitative Developer or Quantitative Analyst.