The Series 66 exam, administered by the Financial Industry Regulatory Authority (FINRA), is a comprehensive licensing examination for individuals seeking to work as investment adviser representatives and securities agents in the United States. Also known as the Uniform Combined State Law Examination integrates elements of the Series 63 and Series 65 exams, covering topics such as ethical practices, fiduciary responsibilities, investment strategies, state securities regulations, and federal securities laws. Candidates, typically sponsored by FINRA member firms, must pass the exam to demonstrate their competency in providing investment advice and conducting securities transactions on behalf of clients. The Series 66 is often taken by individuals who have already passed the Series 7 exam and serves as a crucial requirement for those involved in investment advisory roles, ensuring compliance with state and federal regulations.