Southampton chief executive Martin Semmens has stepped down from his role after the club's relegation to the Championship.
Semmens joined Saints' board of directors in 2017 and was appointed CEO two years later.
The club's owners, Sport Republic, say they will take "full operational control" with immediate effect.
Southampton's 11-year stay in the top flight was ended by a 2-0 loss to Fulham at St Mary's on 13 May.
The club added: "Henrik Kraft will continue as chairman and will act as interim CEO pending the appointment of a new CEO."
Defeat at Brighton on Sunday was Southampton's 12th Premier League game without a win.