The Commission shall have authority from time to time to make, issue, amend, and rescind such rules and regulations and such orders as are necessary or appropriate to the exercise of the functions and powers conferred upon the Commission elsewhere in this subchapter, including rules and regulations defining technical, trade, and other terms used in this subchapter, except that the Commission may not define the term “client” for purposes of paragraphs (1) and (2) of section 80b–6 of this title to include an investor in a private fund managed by an investment adviser, if such private fund has entered into an advisory contract with such adviser. For the purposes of its rules or regulations the Commission may classify persons and matters within its jurisdiction and prescribe different requirements for different classes of persons or matters.