What best defines information barriers in securities?

Information barriers, often referred to as "Chinese walls," are procedures established within firms to prevent the misuse of material nonpublic information (MNPI). These barriers are crucial in the securities industry because they serve to protect sensitive information from being improperly shared between different departments or individuals that could lead to insider trading or other unethical practices.

For instance, a brokerage firm might have analysts and traders who have access to various financial information. If an analyst learns of a significant upcoming merger that has not been disclosed to the public, there needs to be a clear separation between this information and the trading activities of their brokers so that no undue advantage is taken. Information barriers ensure that nonpublic information does not influence trading decisions or market behaviors unlawfully.

Understanding the purpose of these barriers is essential for maintaining the integrity of the markets and ensuring compliance with regulatory requirements. This is why the description highlighting procedures to prevent misuse of MNPI is the most accurate definition of information barriers within the context of securities.