Need Refactoring Services – Software Engineering Stack Exchange

I’ve spent hours on the internet without much luck. Thought I would tap into the collective.

Mu company has a program that is in serious need of refactoring. It’s a deep engineering and predictive analysis desktop program that includes lots of Fortran (two versions), C++, and C# all balled together. It’s been pieced together by a dozen different engineers and programmers for decades and now needs real, special attention. We would like to get it completely into C# for the future. Not my choice of language, but it’s too late now.

I can’t seem to find anyone qualified that would take on such a project. I can see it taking someone from a qualified company well over a year to get it straightened out. They need to at least be USA-based, mid-west preferably, non-disclosure agreement required. Looking for recommendations for companies that might be able to help, thanks.