Pre-print, Working paper: This paper is the seventh chapter of a book forthcoming in January 2007 under the title Histoire du marché financier français au 19 ème siècle (a history of the French capital market in the 19th century). He describes and explains the profound changes undertaken by the banking industry around the mid of the 19th century, and discusses whether they represented an alternative or a complement to the rise of the securities market; it concludes in favour of the second interpretation.