Two Long Island companies — Henry Schein Inc. and Cablevision Systems Corp. — moved up in the rankings of the Fortune 500 list of America’s largest corporations.

Melville-based Henry Schein, a global provider of health care products and services to the office practices of dentists, doctors and veterinarians, rose 19 slots to No. 268.

Bethpage-based Cablevision, a provider of internet and cable TV services in the New York area, climbed 20 spots to No. 399 in the annual listing. Cablevision, whose purchase by Altice Group, a European telecom giant, is awaiting final regulatory approval, is the parent company of Newsday.

Henry Schein and Cablevision were Long Island’s sole representatives on the list.

Walmart topped the list with revenue of $482.1 billion. The retailing giant was followed by energy titan Exxon Mobil with $246.2 billion. Rounding out the top 10 were: Apple, Berkshire Hathaway, McKesson, UnitedHealth Group, CVS Health, General Motors, Ford Motor and AT&T.

The top companies in New York state were: No. 13: Verizon; No. 23: JPMorgan Chase; and No. 29: Citigroup.

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Henry Schein posted net sales in 2015 of $10.63 billion, up from $10.37 billion the prior year. The company’s revenues were $4.1 billion in 2004 when it debuted on the Fortune 500 at No. 487.

Cablevision reported 2015 revenue of $6.51 billion, up from $6.46 billion the prior year when it was ranked No. 419.

The Fortune 500 ranks corporations that are incorporated in the United States based on revenue for their fiscal years.

“Henry Schein continues to rise in the Fortune 500 rankings in large part because of the nearly 19,000 Team Schein members throughout the world,” Henry Schein chief executive Stanley Bergman said in a statement.

Cablevision declined to comment.