Letter dated August 6, 1930 from The Shanghai Commercial & Savings Bank, Ltd. to the Continental Illlinois Bank & Trust Co. to forward the results of the investigation made on several advertising agencies (among which the United Advertising Advicers, just renamed "Consolidated National Advertising Co." after merging with four other agencies in 1930 ; and Carl Crow Inc.). 

In the 1920-1940s, Shanghai banks - such as the Shanghai Commercial & Commercial Bank - were often requested by foreign based banks - such as the Continental Illinois Bank and Trust Co. - to make investigation on Shanghai-based advertising agencies in order to evaluate their solvability. These investigation offer a rich source to document the history of advertising agencies (date of founding, incorporation, status, founder and manager, autorized capital, clients, etc.).