George, a citizen of Mexico, has a sizeable estate that includes the following assets:
− A condominium in Vail, Colorado;
− A house in Mexico City;
− Cash and diamonds located in a safe deposit box in a Houston, Texas bank;
− $2 million of stock in U.S. corporations and $10 million of stock in foreign corporations, held through a brokerage firm located in New York City;
− $500,000 of publicly traded bonds issued by U.S. corporations;
− A $10 million promissory note issued by a Mexican corporation;
− A cause of action for securities fraud and related claims against a U.S. investment advisor;
− A limited partnership interest in a Cayman Islands partnership that owns, among other things, a dog track located in Florida;
− A $20 million policy on his life issued by a U.S. insurance company;
− A $5 million policy insuring the life of his wife issued by a U.S insurance company;
− Certificates of deposit and savings accounts at a bank in Miami, Florida, having a combined balance of $1 million.
George occasionally spends time in the United States attending to his domestic business interests and vacationing with his family. Each trip lasts only a matter of weeks, after which he returns to his home in Mexico City. George gave all of the above-described assets to his children. To what extent, if any, does he owe U.S. gift tax?