U.S.-China economic ties have expanded substantially over the past three decades. Total U.S.-China trade rose from $2 billion in 1979 (when economic reforms began) to $599 billion in 2015. In 2015, China was the United States' second-largest trading partner, its third-largest export market, and its biggest source of imports. According to one source, China is a $400 billion market for U.S. firms when U.S. services exports to China, sales by U.S. foreign affiliates in China, and reexports of U.S. products through Hong Kong to China are factored in. Many U.S. firms view participation in China's market as critical to staying globally competitive. General Motors (GM), for example, which has invested heavily in China, sold more cars in China than in the United States each year from 2010 to 2015. In addition, U.S. imports of lower-cost goods from China greatly benefit U.S. consumers, and U.S. firms that use China as the final point of assembly for their products, or use Chinese-made inputs for production in the United States, are able to lower costs. China is the second largest foreign holder of U.S. Treasury securities ($1.1 trillion as of October 2016), and its purchases of U.S. government debt help keep U.S. interest rates low. Despite growing commercial ties, the bilateral economic relationship has become increasingly complex and often fraught with tension. From the U.S. perspective, many trade tensions stem from China's incomplete transition to a free market economy. While China has significantly liberalized its economic and trade regimes over the past three decades, it continues to maintain (or has recently imposed) a number of state-directed policies that appear to distort trade and investment flows. Major areas of concern expressed by U.S. policymakers and stakeholders include China's alleged widespread cyber economic espionage against U.S. firms; relatively ineffective record of enforcing intellectual property rights (IPR); discriminatory innovation policies; mixed record on implementing its World Trade Organization (WTO) obligations; extensive use of industrial policies (such as financial support of state-owned firms and trade and investment barriers) in order to promote and protect industries favored by the government; and interventionist policies to influence the value of its currency. Many U.S. policymakers argue that such policies adversely impact U.S. economic interests and have contributed to U.S. job losses. There are different views on how the United States could better address commercial disputes with China. Some contend that the United States should take a more aggressive stance against China's trade policies, such as by increasing the number of U.S. WTO dispute settlement cases brought against China, expanding the use of U.S. trade remedy laws on certain imports from China, designating it as a "currency manipulator" and/or threatening to impose sanctions against China unless it addresses various policies, such as cyber theft of U.S. business trade secrets, that hurt U.S. economic interests. Others contend that U.S. trade policy towards China should focus on intensifying and broadening ongoing bilateral dialogues and trade negotiations, such as the U.S.-China Strategic and Economic Dialogue (S&ED), which was established in part to discuss global and bilateral economic and trade issues. Another objective often cited is to complete ongoing bilateral and pluriateral negotiations involving China that would produce agreements expanding market access in China, including a U.S.-China bilateral investment treaty (BIT), China's accession to the WTO's Procurement Agreement (GPA), and a WTO plurilateral environment goods agreement (EGA). This report provides background and analysis of U.S.-China commercial ties, including history, trends, issues, and outlook.