title - Why was this movie called 'The Brothers Bloom'?

This has bugged me since I saw the movie. Why was the movie called 'The Brothers Bloom'?

The brothers are Stephen and Bloom. We are never given their last names and the credits don't show a last name. I would doubt that their last name is Bloom. That would have resulted in 'The Bloom Brothers' though.

Answer

From the IMDb FAQ:

Are the Bloom brothers really brothers?

Yes. At the very beginning of the movie, a caseworker can be seen opening a file cabinet and pulling out the files on young Stephen and Bloom. The file is tagged "Bloom (2)", suggesting that there must be a "Bloom (1)".

Does Bloom have a first name?

The only reference to what Bloom's first name might be comes from a con in which Stephen calls him "Victor." Whether that's his real name or only a contrived name for the con is unknown.

So, it's entirely possible that Bloom wasn't really Brody's first name, but his last name. This would make the title accurate.

I suppose it's not uncommon for people to become known more by their last name than their first. Also, Bloom is certainly not a common first name.

(This question reminds me of the Mario bros., Mario and Luigi.)