of an investment company under section 3 (c) (10) (B) of the Investment Company Act of 1940 (15 USC 80a-3 (c) (10) (B)); except that with respect to the offer or sale of a note, bond, debenture, or other evidence of indebtedness issued by such a person, a rule may be adopted under this chapter limiting the availability of this exemption by classifying securities, persons, and transactions, imposi