No individual other than a citizen of the United States may be an officer of the Corporation. No officer of the Corporation, other than the Chairman or a Vice Chairman, may receive any salary or other compensation (except for compensation for services on boards of directors of other organizations that do not receive funds from the Corporation, on committees of such boards, and in similar activities for such organizations) from any sources other than the Corporation for services rendered during the period of his or her employment by the Corporation. Service by any officer on boards of directors of other organizations, on committees of such boards, and in similar activities for such organizations shall be subject to annual advance approval by the Board and subject to the provisions of the corporation's Statement of Ethical Conduct. All officers shall serve at the pleasure of the Board.