Comcast is a leading provider of cable television, broadband Internet and IP telephony services in the United States. Comcast, which has its headquarters in Philadelphia, Pennsylvania, has 24.6 million cable television customers, 14.4 million broadband Internet users, and 5.6 million subscribers to IP telephony, making it the largest cable television provider in the country. In terms of Internet service providers, Comcast is second only to AT&T in the US.

Time Warner Cable, the second-largest cable provider in the US, was acquired by Comcast for $45.2 billion on February 13, 2014. On June 7, 2017, the 2017 Fortune 500 list of the United States was published, and it was rated number 31. Comcast was rated 11th on April 22, 2018, issue of the list of the world's most profitable corporations. Comcast was ranked 80th on the Fortune 500 list, which was published on July 19, 2018. Comcast was placed 75th on the Fortune 500 list, which was published on July 22, 2019.