Distributed problems in Financial Services?
There is a lots of problems which might be solved by using distributed algorithms. However most of this problems are so specific that there is no existing general purpose tool for all of them.

Banks and some financial institutions keeps their own solutions hidden and i doubt that they would like to share their ideas and code.

For instance let's consider loans, some as far as I know some banks do long term calculations using Markov process. It is possible to compute is on single machine, but those processes are so complicated that I it just wouldn't be effient to calculate them on single machine.

I also found this presentation, you might want to look at it.