Companies such as US Bancorp, Ernst & Young, Aon, Manulife Financial, City National Bank, Wells Fargo, Bank of America, Deloitte, KPMG and the Union Bank of California have offices in the Downtown Financial District.

The economy of Los Angeles is driven by international trade, entertainment (television, motion pictures, video games, and recorded music), aerospace, technology, petroleum, fashion, apparel, and tourism. Los Angeles is also the largest manufacturing center in the western United States. The contiguous ports of Los Angeles and Long Beach together comprise the fifth-busiest port in the world and the most significant port in the Western Hemisphere and is vital to trade within the Pacific Rim. Other significant industries include media production, finance, telecommunications, law, healthcare, and transportation.

The Los Angeles–Long Beach–Santa Ana metropolitan statistical area (MSA) has a gross metropolitan product (GMP) of $735.7 billion (as of 2010), making it the third largest economic center in the world, after the Greater Tokyo Area and the New York-Newark-Bridgeport CSA. If counted as a country, the surrounding CSA has the 15th largest economy in the world in terms of nominal GDP. Los Angeles has been classified an "Alpha world city" according to a 2012 study by a research group at Loughborough University in England.

The city is home to six Fortune 500 companies. They are energy company Occidental Petroleum, healthcare provider Health Net, metals distributor Reliance Steel & Aluminum, engineering firm AECOM, real estate group CBRE Group and builder Tutor Perini.

Other companies headquartered in Los Angeles include 20th Century Fox, American Apparel, California Pizza Kitchen, The Capital Group, Capstone Turbine, The Cheesecake Factory, Cathay Bank, City National Bank, The Coffee Bean & Tea Leaf, Deviant Art, Far East National Bank, Farmers Insurance Group, Group, Gibson, Guess?, Hanmi Bank, Herbalife, J2 Global Communications, The Jim Henson Company, KB Home,Korn/Ferry, Latham & Watkins, Mercury Insurance Group, Oaktree Capital Management, O’Melveny & Myers, Pabst Brewing Company, Paul, Hastings, Janofsky & Walker, Premier America, Premiere Radio Networks, Rentech, Sunkist, The TCW Group, Tokyopop, Triton Media Group, United Online, VCA Antech, and Viking Cruises.

The University of Southern California (USC) is the city's largest private sector employer and contributes $4 billion annually to the local economy.

According to the city's 2010 Comprehensive Annual Financial Report, the top ten employers in the city as of 2009 were, in descending order, the City of Los Angeles, the County of Los Angeles, University of California, Los Angeles, University of Southern California, Cedars-Sinai Medical Center, Kaiser Permanente, Fox Entertainment Group, Farmers Insurance Group, TeamOne, and Northrop Grumman.