Mikhail, a Korean, wishes to be a stockholder in an airline company in the United States. However, he is told that he cannot buy shares of the company as he is neither a U.S. citizen nor a permanent resident of the country. Besides this, he can become a stockholder only if any of the current stockholders decide to sell their shares as the company already has 100 stockholders. Given this information, it can be assumed that Mikhail wants to be a stockholder of a(n) _____.