Amazon has both a self publishing arm (kindle direct) and a traditional publishing arm (amazon publishing). Like most traditional publishers they have a variet

Amazon has both a self publishing arm (kindle direct) and a traditional publishing arm (amazon publishing). Like most traditional publishers they have a variety of imprints (e.g. 47North for Scifi/fantasy). They compete for authors via the same mechanisms other publishers do and have notable non-self published authors (Greg Bear jumps out to me as a scifi fan). I don't know the specific legal contracts involved with 50 Shades of Grey's ebook distribution but I'd assume that Vintage Books bought those rights after they became the publisher for the book.