Haskell has much more of a group inside of a company will use it as their primary environment then adopting it wholesale. Haskell is used extensively in trading with almost every major bank and hedge fund using it, although no one talks about it. It is also extensively used in energy companies.

There are a few companies out there that use it as their primary language such as Tsuru Capital and my company, Alpha Heavy Industries. By definition companies using it as their primary language will be smaller companies. Standard Chartered has a very large Haskell group.