New York Laws
Article 21-A - Fraudulent Transactions in Securities
339-C - Trading by Brokers Against Customers' Orders.

ยง 339-c. Trading by brokers against customers' orders. A broker, who,
being employed by a customer to buy and carry upon margin the stocks,
bonds or other evidences of debt of a corporation, company or
association, while acting as broker for such customer in respect of such
stocks, bonds or other evidences of debt, sells for his own account the
same kind or issue of stocks, bonds or other evidences of debt of such
corporation, company or association, with intent to trade against the
customer's order, or, who, being employed by a customer to sell the
stocks, bonds or other evidences of debt of a corporation, company or
association, while acting as broker for such customer in respect to the
sale of such stocks, bonds or other evidences of debt, purchases for his
own account the same kind or issue of stock, bonds or other evidences of
debt of such corporation, company or association, with intent to trade
against the customer's order, is guilty of a misdemeanor.