explain, Critics of equilibrium models raise concerns about market efficiency, particularly in highly competitive markets resembling models of perfect competition. Behavioral approaches question market efficiency based on human psychology, citing anomalies like asset price bubbles. Information asymmetries in security markets have significant implications, leading to challenges in achieving market efficiency and stability. Principal-agent relationships in capital markets involve households delegating investment decisions to financial intermediaries, introducing information asymmetry and frictions. Institutional arrangements and specialized intermediaries in primary and secondary security markets aim to overcome informational and other frictions, ensuring market integrity and investor protection (187- 190)