Hey Annies! Seen this?
https://www.zerohedge.com/news/2018-12-23/rumors-swirl-mystery-firm-takes-fight-mueller-supreme-court
Shoorly a notable. My bet is it is the Crown Corporation of the City of London!
Here:
"The court's public docket has offered few clues - containing no information on the parties or their attorneys. Tuesday, however, a three-page order revealed that the witness fighting the subpoena is a corporation owned by a foreign state."