There are 4 books in the Ultimate Billionaires series.
The Ultimate Billionaires series does not have a new book coming out soon. The latest book, The Unforgettable Sheikh (Book 4), was published in May 2017.
The first book in the Ultimate Billionaires series, The Cynical Sheikh, was published in January 2017.
The Ultimate Billionaires series primarily falls into the Contemporary Romance genre.