The Trans-Pacific Partnership, known as TPP, is an ambitious trade agreement inspired by the United States to unite 12 Pacific Rim countries.
It aims to establish a free-trade zone, which will cover two-fifths of the world economy and a third of global trade.
Five of the countries taking part in the negotiations are in the Americas:the United States, Canada, Mexico, Chile and Peru.
Two in Oceania: Australia and New Zealand.
And five in Asia: Japan, Brunei Darussalam, Malaysia, Singapore and Vietnam.
In 2008, the United States and the four member countries of the Trans-Pacific Strategic Economic Partnership, known as the P4, announced they would begin negotiating towards a TPP agreement.
In the following years, other countries were invited to join the talks, including Mexico in 2012.
An eventual TPP agreementexpects a combined gross domestic product of 28 trillion U.S. dollars.
Though difference remains, especially on the issues of trade union, auto markets and dairy products, the United States is confident that the agreement will be ready this year.
Meanwhile, China expects the agreement to be transparent and open, and contribute to free trade and investment along with other arrangements in the region.