V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

IFX
       Interactive Financial eXchange (USA, banking)


The Free On-line Dictionary of Computing (30 December 2018):

IFX

   ["Type Reconstruction with First-Class Polymorphic Values",
   J. O'Toole et al, SIGPLAN Notices 24(7):207-217 (Jul 1989)].