Roles and responsibilities in internal control

According to the COSO Framework, everyone in an organization has responsibility for internal control to some extent. Virtually all employees produce information used in the internal control system or take other actions needed to effect control. Also, all personnel should be responsible for communicating upward problems in operations, noncompliance with the code of conduct, or other policy violations or illegal actions. Each major entity in corporate governance has a particular role to play:
Management: The Chief Executive Officer (the top manager) of the organization has overall responsibility for designing and implementing effective internal control. More than any other individual, the chief executive sets the "tone at the top" that affects integrity and ethics and other factors of a positive control environment. In a large company, the chief executive fulfills this duty by providing leadership and direction to senior managers and reviewing the way they're controlling the business. Senior managers, in turn, assign responsibility for establishment of more specific internal control policies and procedures to personnel responsible for the unit's functions. In a smaller entity, the influence of the chief executive, often an owner-manager, is usually more direct. In any event, in a cascading responsibility, a manager is effectively a chief executive of his or her sphere of responsibility. Of particular significance are financial officers and their staffs, whose control activities cut across, as well as up and down, the operating and other units of an enterprise.
Board of Directors: Management is accountable to the board of directors, which provides governance, guidance and oversight. Effective board members are objective, capable and inquisitive. They also have a knowledge of the entity's activities and environment, and commit the time necessary to fulfill their board responsibilities. Management may be in a position to override controls and ignore or stifle communications from subordinates, enabling a dishonest management which intentionally misrepresents results to cover its tracks. A strong, active board, particularly when coupled with effective upward communications channels and capable financial, legal and internal audit functions, is often best able to identify and correct such a problem.
Auditors: The internal auditors and external auditors of the organization also measure the effectiveness of internal control through their efforts. They assess whether the controls are properly designed, implemented and working effectively, and make recommendations on how to improve internal control. They may also review Information technology controls, which relate to the IT systems of the organization. There are laws and regulations on internal control related to financial reporting in a number of jurisdictions. In the U.S. these regulations are specifically established by Sections 404 and 302 of the Sarbanes-Oxley Act. Guidance on auditing these controls is specified in PCAOB Auditing Standard No. 5 and SEC guidance, further discussed in SOX 404 top-down risk assessment. To provide reasonable assurance that internal controls involved in the financial reporting process are effective, they are tested by the external auditor (the organization's public accountants), who are required to opine on the internal controls of the company and the reliability of its financial reporting.

Limitations
Internal control can provide reasonable, not absolute, assurance that the objectives of an organization will be met. The concept of reasonable assurance implies a high degree of assurance, constrained by the costs and benefits of establishing incremental control procedures.
Effective internal control implies the organization generates reliable financial reporting and substantially complies with the laws and regulations that apply to it. However, whether an organization achieves operational and strategic objectives may depend on factors outside the enterprise, such as competition or technological innovation. These factors are outside the scope of internal control; therefore, effective internal control provides only timely information or feedback on progress towards the achievement of operational and strategic objectives, but cannot guarantee their achievement.
Internal control involves human action, which introduces the possibility of errors in processing or judgment. Internal control can also be overridden by collusion among employees (see separation of duties) or coercion by top management.