Sprint will end its partnership with NASCAR after the 2016 season.

The wireless carrier cited a need to focus more directly on its core business priorities as the reason for its decision to end its sponsorship of NASCAR's top series.

NASCAR and Nextel signed a 10-year agreement in 2004 and Sprint took over after a corporate merger with Nextel. The Nextel Cup became the Sprint Cup in 2008.

Prior to 2004, NASCAR's premier series had been sponsored by tobacco giant RJ Reynolds for 33 years and was known as the Winston Cup.