The E category is especially useful for business owners, managers, and employees who need to remain in the United States for extended periods of time in order to oversee or work in an enterprise engaged in trade between the United States and a foreign state or that represents a major investment in the United States. The E nonimmigrant category is available, however, only if a "treaty of commerce and navigation" or a "bilateral investment treaty" providing for nonimmigrant entries is in existence between the United States and the foreign state (except in the case of Sweden and Australia, which are covered even without a treaty).