Сначала посмотрим определение сабжа:

U.S.-owned foreign entity. The term “U.S.-owned foreign entity” means any foreign entity which has one or more “substantial U.S. owners.” A foreign entity is any entity that is not a “U.S. person.”

Substantial U.S. owner. The term “substantial U.S. owner” means the following:
Any corporation, any “specified U.S. person” that owns, directly or indirectly, more than 10 percent of the stock of such corporation (by vote or value)
Any partnership, any “specified U.S. person” that owns, directly or indirectly, more than 10 percent of the profi ts or capital interests in such partnership
Any trust, any “specified U.S. person” treated as an owner of any portion of such trust under the grantor trust rules
To the extent provided by the Secretary, any “specified U.S. person” that holds, directly or indirectly, more than 10 percent of the beneficial interests of the trust3
http://www.taxcareerdigest.com/articles/us_tax_FATCAarticleI...

К слову, обращает на себя внимание то, что в приведенном выше определении сабжа глагол own употребляется наряду с глаголом hold.

Соответственно:

substantial U.S. owner – крупный собственник(, находящийся) под юрисдикцией США

Имхо, как и обычно.