Data sharing rules in CRM define how customer data is accessed, modified, or shared across departments, teams, and external partners. These rules ensure that sensitive information is only available to authorized users while enabling necessary collaboration between sales, marketing, and customer service teams. Businesses use role-based access controls (RBAC) and hierarchical permissions to enforce data sharing policies. For example, a sales representative may have access to their assigned leads but not to company-wide customer records. Properly implemented data sharing rules prevent data leaks, enhance security, and maintain compliance with industry regulations such as GDPR and CCPA.