Later in the same year, John Jacob Astor purchased Fort Kiowa from Pratte for his rapidly expanding American Fur Company. Astor, who was the first multi-millionaire in America, bought Fort Kiowa to establish his presence in the upper Missouri and to further his monopoly on the American fur trade. Astor found the upper Missouri river area to be extremely prosperous. However, in the late 1830s, Astor’s American Fur Company was forced to abandon Fort Kiowa as the once lucrative fur trading business was no longer profitable due to several factors. First, there was a scarcity of beaver caused by rapid overhunting by intruding trappers. Second, there was a lack of public demand in America and Europe for pelts, as a new style, silk hats, was gaining prominence. Lastly, the intrusion of American trappers on what natives perceived as their land angered native tribes who began to revolt against the trappers. As supply and demand both declined, fur trading in America faced extinction.