Nationalist critics believe the Act is too narrow and, as a matter of policy, should more heavily restrict foreign investment.
He said he did not know why the government oil company "would want to restrict investment and production."
Nations frequently restrict immigration, capital flows, and foreign direct investment.
Because many of these companies sell to markets other than the defense industry, government efforts to restrict foreign investment in them would be difficult to regulate.
The main reason given for restricting investment in new technology was cost.
Mexico nationalized its oil industry in 1938, and has never privatized, restricting foreign investment.
Closed-end funds have become a popular way to enter the stock market of many countries, especially those that restrict foreign investment.
The party would also sharply restrict foreign investment, particularly in consumer goods and services.
Such higher rates could restrict economic growth and investment, making it even harder to reduce unemployment.
Administration officials, however, were quick to observe that Japan restricts foreign investment in its economy.