Finding graduate programs supporting a specific research focus
Three easy suggestions:


Look for advisors, not programs.  It's unlikely that any department is going to have a separate program, or even a separate research group, with your particular focus.   Look for authors of papers that you've read about financial systems and machine learning.  (You have read such papers, haven't you?)  Then look at the authors they cite, and the authors that cite them.
Don't limit yourself to computer science departments.  If you do good research, nobody cares what department is listed on your diploma.  (And if you don't plan to do good research, you don't really want a PhD.)  Lots of faculty and students in non-CS departments do excellent computer science research.
Ask your faculty mentors.  After working at six universities, you've built a large professional academic network; exploit it!  Your faculty colleagues will be considerably more familiar with programs in their (and your) particular focus than Random Strangers on the Internet.