C++ and Java for the most part. However, I'm not sure that finance hoovering up all the Haskell programmers (even if that were true) would have any impact on t

C++ and Java for the most part. However, I'm not sure that finance hoovering up all the Haskell programmers (even if that were true) would have any impact on that. The number of Haskell programmers, in total, is small compared to the number of C++ and Java programmers in finance. It also may be worth pointing out that finance companies, especially larger ones, are rarely homogeneous in their development environments. For example, the Haskell wiki's industry page has the names of a large number of banks that use Haskell. I have worked at a few of them and know a fair number of people at others and I don't know anyone that does any production Haskell. Plenty of Java, C++, Python, C# and Scala though.