[everforward]

It depends on which area of the business you're in.

The quants (people who do the analysis to give buy/sell signals, basically, typically using programming for the analysis) will generally need a strong grasp of statistics and finance.

The developers that build the trading platform will need a strong grasp of exchanges and the mechanics of trading, but not really of statistics or "how the market works/reacts".

The developers that work on the reporting side don't really need a strong grasp of either. The math is relatively simple, the difficult part is handling stuff like cross trades. I.e. internally trading stocks between portfolio managers without having to hit the actual exchange (i.e. PM A wants to sell Intel, and PM B wants to buy, so you just transfer ownership instead of actual buy/sell orders). You have to attribute a profit/loss to PM A even though there wasn't a "real" profit or loss.

The SRE/ops side often doesn't require much knowledge of finance or math. The apps aren't particularly unique, and the portions of the trading flow you're expected to know aren't hard to pick up in a month or two. You aren't typically expected to have an in-depth understanding of trading strategy, or a highly detailed understanding of how trading works mechanically. Knowing that stuff probably lets you command a higher salary and title, but it isn't a prerequisite.