Walmart kept its lock on the top ranking of the Fortune 500 annual list of the largest US companies, while Apple was the most profitable and Facebook the most upward-bound, Fortune Magazine announced.

Retail behemoth Wal-Mart Stores remained in the number one spot for the third year in a row, based on company revenues last year of $485.6 billion.

The put it ahead of number-two ExxonMobil, with $382.6 billion, and then Chevron, Berkshire Hathaway and Apple, in a top five ranking that was unchanged from 2014.

The biggest jump was notched by Facebook, which climbed from 341 to 242. New entrants included emerging tech heavyweights Salesforce.com, Netflix and Expedia.

While Walmart was the largest by revenues, Apple's $39.5 billion in profits led the pack, followed by Exxon with $32.5 billion. Microsoft, Google, IBM, Intel and Oracle all placed in the top 20 in profits while outside the top 20 by revenue.

The companies in the Fortune 500 had total revenues of $12.5 trillion in 2014, up 2.6 percent from last year and an all-time record.

Total profits were down 12.6 percent to $945 billion.