Are you asking why an arbitrary group of American companies, popularized in an American TV show about the American stock market, has only American companies? I don't know. That's a good question. Why didn't they include others like Tencent, Alibaba, TSMC, Samsung, or BYD?

It's like asking why are the Fortune 500 companies all American companies. In contrast, Fortune Global 500, using the same criteria but in a wider pool, has companies from other counties.