This graph line aims to show the gradual development of advertising agencies in Shanghai. Their number more than doubled in the 1920s, then reached a climax in the 1930, and started to decline during the war 1937-1945. Yet the role of advertising agencies as central actors in the advertising profession was well established. The decline is mainly due to the departure of foreigners during the war, especially after the United States entered the war in Dec 1941, and after the restitution of foreign settlements in 1943. In 1956, the number of agencies was drastically reduced from about 60 to only 4, through a process of merging summoned by the governement at a national scale.

The figures are based on the Shanghai Municipal Archives and other secondary sources (Bankers' Directory, 1933; Hong List, 1941; Morgan, 2003).