Any bank holding company which was registered with the Federal Reserve Board as a bank holding company as of December 31, 1981, and as of that date lawfully owned or controlled at least two Illinois banks or any Illinois bank holding company or companies may, on or after January 1, 1982, continue to own shares of such Illinois bank or banks or of such bank holding company or companies; acquire additional shares of such Illinois bank or banks; and, acquire control of, directly or indirectly, an existing Illinois bank or banks.