Rivals.com's Chris Clark added Muschamp will receive a $200,000 raise "in each successive year."
Muschamp initially signed a five-year deal that paid out $3 million annually, according to The State, but he earned a sizable raise following a strong showing during his second season on the job.
Following a 6-7 effort in 2016, Muschamp led the Gamecocks to a 9-4 finish and secured the program's first winning season since Steve Spurrier was at the helm in 2014.
The 2017 campaign also featured a 26-19 win over the Michigan Wolverines in the Outback Bowl on New Year's Day.
Muschamp will now set his sights on helping the Gamecocks reach double-digit wins for the first time since 2013 as they prepare to welcome 247Sports' 18th-ranked recruiting class.