According to information from the Congressional Research Service report on March 29, 2011: “The 9/11 attacks cost the United States at least $1 trillion through direct property damage and second-order economic consequences, including the impact on the stock market. Thereafter, budgetary outlays for the military operations in Afghanistan and Iraq that were undertaken as a response to al Qaeda’s attacks have been about $1.3 trillion.”
– Daveed Gartenstein-Ross, Bin Laden’s Legacy, Page 14