Visa is a well-established service provider in the banking vertical. London, United Kingdom is the location of their main location.
Right now, Financial Data Analysis, Software Architecture, and Software Engineering are frequently searched for professions at Visa. They recruit for offices in Foster City, CA, Singapore, Austin, TX and 18 other locations within Mexico and other countries. See below for a list of 191 job offers at Visa for jobs like "Security Specialist, Infrastructure" and "Systems Analyst -- REF7313Y".
Wikipedia provides a helpful article about Visa. Check out their social profile on Crunchbase for a different perspective. A resource not to neglect is the company's careers page with more information about job offers and career prospects.