I've heard of Malbolge. I first became aware of it when it was mentioned in an episode of Sherlock. Supposedly banks use it for their software. Okay, whatever.

And then it was mentioned in an episode of Elementary. Supposedly banks use it for their software. I had to look it up.

Given that it's not even known whether Malbolge is Turing-complete, it's doubtful banks would actually use it. Banks are likelier to use Visual Basic.