17 CFR §1.56

1. (a)[Reserved]
2. (b)No futures commission merchant or introducing broker may in any way represent that it will, with respect to any commodity interest in any account carried by the futures commission merchant for or on behalf of any person:
   1. (1)Guarantee such person against loss;
   2. (2)Limit the loss of such person; or
   3. (3)Not call for or attempt to collect initial and maintenance margin as established by the rules of the applicable board of trade.
3. (c)No person may in any way represent that a futures commission merchant or introducing broker will engage in any of the acts or practices described in paragraph (b) of this section.
4. (d)This section shall not be construed to prevent a futures commission merchant or introducing broker from:
   1. (1)Assuming or sharing in the losses resulting from an error or mishandling of an order; or
   2. (2)Participating as a general partner in a commodity pool which is a limited partnership.
5. (e)This section shall not affect any guarantee entered into prior to January 28, 1982, but this section shall apply to any extension, modification or renewal thereof entered into after such date.