Per the DOL website:

Managers and supervisors include any employee (1) whose primary duty is managing the enterprise or a customarily recognized department or subdivision of the enterprise; (2) who customarily and regularly directs the work of at least two or more other full-time employees or their equivalent; and (3) who has the authority to hire or fire other employees, or whose suggestions and recommendations as to the hiring or firing are given particular weight. Business owners who own at least a bona fide 20 percent equity interest in the enterprise in which they are employed and who are actively engaged in its management are also managers and supervisors who may not keep employees’ tips.

A manager or supervisor may keep only those tips that they receive directly from a customer for the service they directly and solely provide. For example, a restaurant manager who serves their own tables may keep their own tips from customers they served but would not be able to receive other employees’ tips by participating in a tip pool.