Final answer:
The ultimate ownership of an internal control system should rest with the board of directors, but it should be noted that top executives often influence board selection. No control system can provide 100 percent assurance of meeting objectives due to potential external and internal factors.
Step-by-step explanation:
The question poses whether ultimate ownership of an internal control system should rest with the board of directors, and if a properly implemented system provides 100 percent assurance that the organization will meet its objectives. Concerning the first part of the question, it is generally accepted that the board of directors should have the ultimate ownership of an internal control system as they are elected by the shareholders to oversee the firm's management and operations, ensuring they run in the shareholders' interests. However, it is also true that top executives often have significant influence in selecting board members, which can create conflicts of interest. With regards to the second part, no internal control system can guarantee 100 percent assurance of achieving organizational goals, as there are always outside factors and potential internal oversights that can affect outcomes, as was evident in the failure of corporate governance at Lehman Brothers.