Possessives and Attributives

Q. When forming the possessive for a proper noun rendered with an initialism, should I use ’s, or, because the last word rendered by the initialism is “Services,” should I treat it as a noun plural in form but singular in meaning, and add the apostrophe only? My instinct is to write “FIS's customers” because, plural services or no, FIS is one company. However, on that company's website I see that they form the possessive with the apostrophe only: “FIS' competitive edge.” Thank you for any advice.

A. Your instincts are right: when you are working with initialisms, the trick is to ignore what the letters stand for. In your case, you are no longer talking about Friendly and Ineffectual Services' customers; you're talking about FIS's customers.