For purposes of this subchapter, an alien insurer is considered to be organized in the state designated by the insurer in which the insurer:
(1) has established its principal office or agency in the United States;
(2) maintains the greatest amount of its assets held in trust or on deposit for the security of its policyholders or policyholders and creditors in the United States; or
(3) was admitted to engage in business in the United States.