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, Scientific Method, and Data Analysis are frequently searched for professions at Visa. They recruit for offices in Foster City, CA, Austin, TX, Singapore and 18 other locations within South Africa and United Kingdom. See below for a list of 289 job offers at Visa for jobs like "QA Engineer" and "Senior FP&A Manager (Reporting) - 12 Month Contract".
Wikipedia provides a helpful article about Visa. Check out their social profile on Google Plus for a different perspective. A resource not to neglect is the company's careers page with more information about job offers and career prospects.