The Trans-Pacific Partnership (TPP) is a proposed regional free trade agreement (FTA) among 12 countries: Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States, and Vietnam. The negotiating partners have expressed an interest in allowing this proposed “living agreement” to cover new trade topics and to include new members that are willing to adopt the proposed agreement’s high standards. Japan is the most recent country to seek entry into the TPP. The Administration gave Congress notice of its intent to negotiate with Japan in the TPP on April 24, 2013. The TPP negotiations have been of significant interest to Congress. Congressional involvement includes consultations with U.S. negotiators on and oversight of the details of the negotiations, and eventual consideration of legislation to implement the final trade agreement. In assessing the TPP negotiations, Members may be interested in understanding the potential economic impact and significance of TPP and the economic characteristics of the other TPP countries as they evaluate the potential impact of the proposed TPP on the U.S. economy and the commercial opportunities for expansion into TPP markets.