The responsibilities of an organization's CEO are set by the organization's board of directors or other authority, depending on the organization's structure. They can be far-reaching or quite limited and are typically enshrined in a formal delegation of authority regarding business administration. Typically, responsibilities include being a decision maker on business strategy and other key policy issues, leader, manager, and executor. The communicator role can involve speaking to the press and the rest of the outside world, as well as to the organization's management and employees; the decision-making role involves high-level decisions about policy and strategy.
As an executive officer of the company, the CEO reports the status of the business to the board of directors, motivates employees, and drives change within the organization. As a manager, the CEO presides over the organization's day-to-day operations. The CEO is the person who is ultimately accountable for a company's business decisions, including those in operations, marketing, business development, finance, human resources, etc.
The CEO of a company is not necessarily the owner or the head of the company. The CEO of a political party is often entrusted with fundraising, particularly for election campaigns.