May 16 (UPI) -- Fortune magazine released its annual list Thursday of the top 500 U.S. companies, and it includes more female chief executives than ever before.
The annual list, which ranks companies by revenue, showed retail giant Walmart is the clear No. 1, with $514.4 billion last year -- nearly twice the revenues of the No. 2 company, ExxonMobil ($290.2 billion). Apple ($265.6B), Berkshire Hathaway ($247.8B) and Amazon ($232.9B) round out the top five.
UnitedHealth ($266.2B), pharma company McKesson ($208.3B), CVS Health ($194.5B), AT&T ($170.7B) and AmerisourceBergen ($167.9B) completed the top 10.
Amazon was the greatest mover on this year's list, jumping from No. 8 last year to fifth.
The ranking includes more companies with female CEOs, 33, than ever before -- one more than the previous record set two years ago.
Fortune said only 500 companies produced enough revenue make this year's list, equaling two-thirds of the United States' total economic output.
"These same American businesses sold an astounding $13.7 trillion worth of goods and services, a record sum whether you measure it in nominal dollars or adjusted for inflation," Fortune said in a statement. "But focus in on the numbers and you'll discover something yet more remarkable: that just a 10th of these companies account for nearly half (48 percent) of that total revenue."
Fortune said six on the list own at least $1 trillion in assets, roughly equal to the gross domestic product of some countries.
Automaker Ford surpassed rival General Motors on this year's list -- ranked No. 12 (down from 11th a year ago) as GM fell to 13th (down from No. 10).