say they expect Cantor to tell his colleagues he will resign from the position at a meeting of House Republicans at 4 p.m. ET.
Cantor, a Virginia Republican, has served as second-in-command to House Speaker John Boehner since 2010. He was defeated in the primary by David Brat, a little-known economics professor who ran a shoestring campaign without the support of prominent national Tea Party groups.
The decision, first reported by the Washington Post, is sure to send shockwaves through Capitol Hill as members of the conservative and establishment wings of the Republican Party jockey to fill the influential post.
Cantor had previously been discussed as a potential successor to Boehner if the current speaker stepped down.