I was just thinking, the only ones I can imagine taking ownership would be one of the "big internet foundations" that have earned their trust: Mozilla, the Internet Archive, Wikimedia, or the EFF. Of those, Mozilla and the EFF are the only ones that make real sense. I hope it's one of them, and not fucking Norton AntiVirus or whatever.
A Mozilla acquisition of HIBP could look alot like Mozilla buying HIBP from them, and then bringing Troy on board for a period of time as an evangelist, and the nature of being an open source, community focused org means that Troy could retain his ties to Mozilla as long as he wants to, as a staff member or volunteer.
I don't know how much has changed since I left Mozilla, but there were, and probably still are, a number of former employees and volunteer contributors that had a great degree of influence and input on various projects.
Heck, Troy might even be a good potential addition to the Mozilla board of directors at some point in the future.
It calls to mind the trust in Jon Postel, who managed DNS through IANA for about 10 years basically alone until his death in 1998 and IANA's subsequent transfer to ICANN (which had just been founded).
Since Troy will still be involved, hopefully he can steer things in a direction that benefits everyone - or at least warn the public otherwise.
Maybe an organisation not involved in advertising at any level.