In this paper we analyze whether the Softwood Lumber Agreement between US and Canada imposed significant economic costs on the users of Lumber in the US. To ascertain this impact we use an event study. Our event study analyzes variations in the stock prices of lumber using firms listed at the major stock markets in the US. We find that events leading to the Softwood Lumber Agreement had significant negative impacts on the stock prices of industries using softwood lumber. The average reduction of stock prices for our sample of firms was approximately 5.42% over all the events considered.