Harry Potter Publishers

[Joe Bento]

This is likely a question that has been asked and answered before, but
I've been unable to find any information.

Bloomsbury is the publisher of the books in the UK as well as the
original and first publisher of the books.

Bloomsbury has a USA branch.

Since I am ignorant about how publishing works, how was Scholastic
chosen for the US publisher rather than Bloomsbury USA?  For that
matter, Scholastic has a UK branch. So same question applies.

Joe