If you have something with 40M customers I'd highly recommend going with the same domain registrars used by some of the Fortune 100 companies.
Seizing a domain at the registrar level, by court order, is also how the US government implements "seizure" of domains, if you've ever seen a torrent index site that has suddenly been replaced with a big scary FBI page (examples: https://www.google.com/search?q=this+domain+has+been+seized+... )