73. A broker who buys and carries on margin, for a customer, securities of any company or undertaking in Canada or elsewhere, must not sell or cause to be sold, for any account in which he has a direct or indirect interest, securities of such company or undertaking which he also holds on margin, if such sale would have the effect of reducing below the amount which the broker should be carrying for all his customers, the amount of securities, rights or interest which he has in his possession or under his control, for such customer, in the ordinary course of business.
R. S. 1964, c. 274, s. 56.