High Quality Content by WIKIPEDIA articles! The economy of the United States is the world`s largest national economy. Its nominal GDP was estimated to be nearly $14.5 trillion in 2010, approximately a quarter of nominal global GDP. The European Union has a larger collective economy, but is not a single nation. Its GDP at purchasing power parity was also the largest in the world, approximately a fifth of global GDP at purchasing power parity. The U.S. economy also maintains a very high level of output per capita. In 2010, it was estimated to have a per capita GDP (PPP) of $46,844, the 7th highest in the world. The U.S is the largest trading nation in the world. Its three largest trading partners as of 2010 are Canada, China and Mexico.