Southern Miss is the first school to officially leave Conference USA and join the Sun Belt, sources told The Action Network's Brett McMurphy.
The school is reportedly set to begin conference play in the Sun Belt in 2023 after being accepted as a member on Friday.
Other C-USA members Old Dominion and Marshall as well as FCS member James Madison are reportedly also expected to join, though they have not officially applied for membership.
The report comes after six schools announced their departure from C-USA to move to the American Athletic Conference on Thursday.
With nine schools potentially leaving the conference, only five schools remain in C-USA: FIU, Louisiana Tech, Middle Tennessee, UTEP, and Western Kentucky. C-USA must add new schools to remain an FBS conference.
