Excerpt from The Verge
Written by Andrew Liptak
During a special fan event for Fantastic Beasts and Where to Find Them, Harry Potter author J.K. Rowling pulled the equivalent of Steve Jobs’ "One more thing," and dropped some hints about what the future of the franchise might look like: she’s planning a total of five films, rather than three.
Rowling revealed the news at the end of the event (50:46 mark):
We always knew that it was going to be more than one movie — we knew that from the start — so we set a trilogy as a sort of placeholder, because we knew there would be more than one movie. But we’ve now, I’ve now done the plotting properly, so we’re pretty sure it’s going to be five movies.