A restriction on the transfer of securities of a corporation, or on the amount of a corporation’s securities that may be owned by any person or group, is …

1. … enforceable against
   • a person with actual knowledge of the restriction, and
   • anybody if the restriction is noted conspicuously on the certificate(s) representing the restricted securities or, in the case of uncertificated shares, contained in the notice(s) given pursuant to § 151(f).
2.   … imposable by the charter, the bylaws, or an agreement among any number of security holders or among such holders and the corporation. Securities issued prior to the adoption of the restriction are bound by it only if their holders are parties to an agreement or voted in favor of the restriction.
3. / e. … permitted if it is lawful, in particular if it:
   1. obligates the holder of the restricted securities to offer to someone “a prior opportunity, to be exercised within a reasonable time, to acquire the restricted securities;”
   2. obligates someone “to purchase the securities which are the subject of an agreement respecting the purchase and sale of the restricted securities;”
   3. requires the corporation or the holders of any class or series of securities of the corporation to consent to any proposed transfer or transferee of the restricted securities, or to approve the amount of securities of the corporation that may be owned by any person or group of persons;
   4. obligates the holder of the restricted securities to sell or transfer an amount of restricted securities to someone, or causes or results in the automatic sale or transfer of an amount of restricted securities to someone; or
   5. prohibits or restricts the transfer of the restricted securities to, or their ownership by, designated persons or classes of persons, and such designation is not manifestly unreasonable.
4. … conclusively presumed to be for a reasonable purpose if it is for the purpose of maintaining any …
   1.   … tax advantage (local, state, federal or foreign) to the corporation or its stockholders, including:
      1. the corporation’s status as an S-corporation, or
      2. any tax attribute (including net operating losses),
      3. the qualification of the corporation as a real estate investment trust pursuant to the US Internal Revenue Code or regulations adopted thereunder, or
   2.   … statutory or regulatory advantage or complying with any statutory or regulatory requirements under applicable local, state, federal or foreign law.