A securities association registered under section
78o–3 of this title may prescribe, by rules adopted and in effect in accordance with said section and subject to all provisions of said section applicable to the rules of such an association—
in each case for the purpose of eliminating or reducing so far as reasonably practicable any dilution of the value of other outstanding securities of such company or any other result of such purchase, redemption, or sale which is unfair to holders of such other outstanding securities; and said rules may prohibit the members of the association from purchasing, selling, or surrendering for redemption any such redeemable securities in contravention of said rules.