Hey everybody,
thanks so much for your responses!
Believe it or not, just minutes ago BMI actually got back to me and wrote this:
No you do not need to obtain an ITIN. Please just complete a W-8BEN that has your German tax ID number in box 6.
So markdorricott’s answers seem to be spot on…!
Hopefully this thread will be helpful for others with the same question.
Thanks and have a great day!