The 25 Biggest Tech Companies On The Fortune 500


21. CenturyLink

Fortune 500 Rank: No. 150

Revenue: $18.4 billion

Top Executive: President and CEO Glen Post

Monroe, La.-based CenturyLink greatly improved its ranking from No. 171 last year. But, the Internet service provider found itself in the news earlier this month when as many as 1 million CenturyLink customers in 22 states found themselves without broadband service for several hours in an outage the Internet service provider blamed on a problem with its core routers.