7-Eleven is looking for a new agency to handle its creative business, according to people with knowledge of the matter.

Mzyme Marketing is supporting the review, which is expected to wrap in early December, according to the same people. Representatives from Mzyme Marketing were not immediately available for comment.

Earlier this year, JWT worked with 7-Eleven, developing creative for the brand's March Madness sandwich effort and a hot dog campaign. JWT declined to comment about the current review.

7-Eleven, which spent about $22 million on measured media in 2015, according to Kantar Media, did not respond to inquiry for comment.

7‑Eleven Inc. has about 10,700 convenience stores in North America. The Irving, Tex.-based retailer, which gets its name for its hours of operation (7 a.m. to 11 p.m.) when it opened in 1946, is known to many for road trip standbys such as Slurpee and Big Gulp. 7-Eleven is owned by Japan's Seven & I Holdings Co.

The retailer says it was the first convenience store to air a TV spot, an animated commercial with a singing owl and a rooster that ran in 1949.

7-Eleven's U.S. retail sales were $13.96 billion in 2015, according to Kantar Retail data published by the National Retail Federation.