46 U.S.C. § 50501 — Entities deemed citizens of the United States

(a) In General. A corporation, partnership, or association counts as a U.S. citizen only if U.S. citizens own the controlling interest. But if it operates a vessel^* in the coastwise trade — shipping between U.S. ports — U.S. citizens must own at least 75 percent of the interest.

(b) Additional Requirements for Corporations. A corporation must meet the rules in (a) and also:
(1) be incorporated under U.S. or state^* law;
(2) have a CEO and a board chairman who are both U.S. citizens; and
(3) have noncitizen directors number less than a minority needed for a quorum — in other words, noncitizens can't come close to blocking a quorum on their own.

(c) Determination of Controlling Corporate Interest. To show U.S. citizens control the corporation under (a), all four of these must be true:
(1) U.S. citizens hold title to most of the stock, free of any trust or fiduciary duty owed to a noncitizen;
(2) U.S. citizens hold most of the voting power;
(3) no contract or understanding lets a noncitizen exercise most of the voting power, directly or indirectly; and
(4) there's no other way a noncitizen controls the corporation.

(d) Determination of 75 Percent Corporate Interest. To show U.S. citizens own at least 75 percent under (a), all four of these must be true:
(1) U.S. citizens hold title to at least 75 percent of the stock, free of any trust or fiduciary duty owed to a noncitizen;
(2) U.S. citizens hold at least 75 percent of the voting power;
(3) no contract or understanding lets a noncitizen exercise more than 25 percent of the voting power, directly or indirectly; and
(4) there's no other way a noncitizen controls more than 25 percent of any interest in the corporation.