What led john jacob astor to corner the fur-trading market? 1) the establishment of fort astoria gave astor an edge in the pacific northwest.2) the lifting of the embargo act of 1807 had reduced the cost of furs. 3)jay’s treaty had stopped british trappers from trading in america.4) french fur trappers had left after the sale of the louisiana territory. i already tried the first one and that was incorrect. edit: i figured out the answer it was 3) jay’s treaty had stopped british trappers from trading in america.