37 CFR § 11.506 - Restrictions on right to practice.
A practitioner shall not participate in offering or making:
(a) A partnership, shareholders, operating, employment, or other similar type of agreement that restricts the right of a practitioner to practice after termination of the relationship, except an agreement concerning benefits upon retirement; or
(b) An agreement in which a restriction on the practitioner's right to practice is part of the settlement of a client controversy.
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