An activist investor is an individual or group that invests in a company with the intention of influencing changes within the organization to increase its value. They typically take an active role in the management and operations of the company, often by agitating for change through shareholder proposals, proxy fights, or public campaigns. Activist investors may push for changes such as increased dividends, stock buybacks, restructuring, or even a complete sale of the company. Their goal is to create value for themselves and other shareholders by improving the financial performance and long-term prospects of the business.