Which company operates under the name of Compagnie Financière Tradition?

Tradition is the company that operates under the name of Compagnie Financière Tradition. This firm is a global leader in the interdealer broking industry, primarily engaged in the trading of various financial instruments. The name Compagnie Financière Tradition represents the parent company, under which the Tradition group operates its various subsidiaries.

The significance of this is found in the company's history and branding. While it may be associated with other firms in related sectors, such as interdealer broking, the distinguishing identity as Compagnie Financière Tradition is tied directly to the Tradition name. The other companies listed, like Tullett Prebon, BGC Partners, and GFI Group, are separate entities in the financial services sector and do not operate under the Compagnie Financière Tradition name. Thus, the recognition of Tradition as the correct answer highlights the direct relationship and branding under which the company conducts its business activities.